Protein profiling of preeclampsia placental tissues

Magnetic blood purification-based soluble fms-like tyrosine kinase-1 removal in comparison with dextran sulfate apheresis and therapeutic plasma exchange

BACKGROUND

Preeclampsia remains one of the most serious complications of pregnancy. Effective therapies are yet to be developed. Recent research has identified an imbalance of angiogenic and antiangiogenic factors as a root cause of preeclampsia. In particular, soluble fms-like tyrosine kinase-1 (sFlt-1) has been shown to bind the angiogenic factors vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), reducing blood vessel growth. Increasing preclinical and clinical evidence suggests that removal of the sFlt-1 protein may benefit patients with early onset preeclampsia. sFlt-1 may be removed by conventional blood purification techniques, such as therapeutic plasma exchange (TPE) and dextran sulfate apheresis (DSA), or emerging technologies, including extracorporeal magnetic blood purification (MBP).

METHODS

We compare the performance and selectivity of TPE, DSA, and MBP for the therapeutic removal of sFlt-1. For MPB, we employ magnetic nanoparticles functionalized with either sFlt-1 antibodies or the sFlt-1-binding partner, vascular endothelial growth factor (VEGF).

RESULTS

We demonstrate that sFlt-1 removal by MBP is feasible and significantly more selective than TPE and DSA at comparable sFlt-1 removal efficiencies (MBP 96%, TPE 92%, DSA 78%). During both TPE and DSA, complement factors (incl. C3c and C4) are depleted to a considerable extent (-90% for TPE, -55% for DSA), while in MBP, complement factor concentrations remain unaltered. We further demonstrate that the removal efficacy of sFlt-1 in the MBP approach is strongly dependent on the nanoparticle type and dose and can be optimized to reach clinically feasible throughputs.

CONCLUSIONS

Taken together, the highly selective removal of sFlt-1 and potential other disease-causing factors by extracorporeal magnetic blood purification may offer new prospects for preeclamptic patients.

Integrated Proteomic and N-Glycoproteomic Profiling of Placental Tissues of Patients with Preeclampsia

Background

Preeclampsia (PE) is a multi-system disorder of pregnancy that poses a serious threat to maternal and perinatal health worldwide. This study aims to evaluate the global alterations of protein expression and N-glycosylations that are crucial for PE pathogenesis. Here, tandem mass tag labeling combined with LC-MS/MS was employed to determine the global expression of all proteins and intact glycopeptide in placentas from three healthy pregnant women, three patients with early-onset severe PE, and three patients with late-onset severe PE.

Results

A total of 2260 proteins were quantified across 9 placental tissues, of which 37 and 23 were differentially expressed in the early-onset and late-onset PE groups, compared to the controls. A total of 789 glycopeptides were accurately quantified, which were derived from 204 glycosylated sites in 159 glycoproteins and were modified by 59 N-Linked glycans. A total of 123 differently expressed glycopeptides, which were from 47 glycoproteins were identified among three groups. Through a combined analysis of proteomic and glycoproteomic data, it was found that the changes in 10 glycoproteins were caused by the difference in glycosylation level but not in the protein abundance level.

Conclusion

This is the first study to conduct an integrated proteomic and glycoproteomic characterization of placental tissues of PE patients. Our findings suggest that glycosylation modification may affect the molecular function of proteins through changes in the glycosylation structure or the occupancy of glycosylation, which will provide new insights to help elucidating the pathogenic mechanism of PE.

G-Protein Coupled Receptor Dysregulation May Play Roles in Severe Preeclampsia-A Weighted Gene Correlation Network Analysis of Placental Gene Expression Profile

Preeclampsia is one of the major hypertensive diseases of pregnancy. Genetic factors contribute to abnormal placentation. The inadequate transformation of cytotrophoblasts causes failure of maternal spiral arteries’ remodeling and results in narrow, atherotic-prone vessels, leading to relative placental ischemia. This study aims to explore the possibility of identifying dysregulated gene networks that may offer a potential target in the possible prevention of preeclampsia. We performed a weighted gene correlated network analysis (WGCNA) on a subset of gene expression profiles of placental tissues from severe preeclamptic pregnancies. We identified a gene module (number of genes = 402, GS = 0.35, p = 0.02) enriched for several G-protein-coupled receptor (GPCR)-related genes with significant protein–protein molecular interaction (number of genes = 38, FDR = 0.0007) that may play key roles in preeclampsia. Some genes are noted to play key roles in preeclampsia, including LPAR4/5, CRLR, NPY, TACR1/2, and SFRP4/5, whose functions generally relate to angiogenesis and vasodilation or vasoconstriction. Other upregulated genes, including olfactory and orexigenic genes, serve limited functions in the disease pathogenesis. Altogether, this study shows the utility of WGCNA in exploring possible new gene targets, and additionally reinforces the feasibility of targeting GPCRs that may offer intervention against development and disease progression among severe preeclampsia patients.

Maternal Immune System and State of Inflammation Dictate the Fate and Severity of Disease in Preeclampsia

Preeclampsia, a multisystem disorder in pregnant women, is diagnosed by onset of new hypertension, proteinuria, or organ damage. Antiangiogenic factors, such as soluble fms-like tyrosine kinase 1 (sFlt1) and soluble endoglin (sEng), are long known to be involved in preeclampsia. However, the role of maternal immune system and inflammation in promotion of preeclampsia has lately been a subject of immense interest. Link between maternal inflammation and preeclampsia is not well established. Furthermore, whether cigarette smoke promotes inflammation and also promotes severity of preeclampsia remains an open question. We herein investigated correlation of established inflammation signatures in the plasma and placental tissue from cohorts of preterm preeclampsia (PPE) and preterm pregnancies (control) with or without smoking history. Besides confirming increased levels of Flt1 and Eng in preeclampsia, we also observed an increase in various mediators of maternal inflammation in women with PPE compared to preterm cohort. Increased IL-6, IL-35, and TNF-α and reduced IL-10 in serum and higher MMP-12, TLR4, HMGB-1, and iNOS and lower Foxp3, CD56 transcripts in placental tissues of PPE compared to preterm pregnancies indicate an association of preterm preeclampsia with stark imbalance in maternal immune system and signatures of inflammation. Smoker PPE cohorts showed highest inflammatory signatures including statistically significant increase for many signatures compared to other cohorts. Together, these results provide evidence for association of inflammation with PPE and strong correlation of smoking with inflammatory signatures in PPE.

TGFb1 suppresses the activation of distinct dNK subpopulations in preeclampsia

BACKGROUND

Decidual natural killer (dNK) cells are the predominant lymphocytes accumulated at the maternal-fetal interface. Regulatory mechanism of dNK cells in preeclampsia, a gestational complication characterized by high blood pressure and increased proteinuria occurring after 20 weeks pregnancy, is not completely understood.

METHODS

Multi-parameter flow cytometry is applied to investigate the phenotype and function of dNK cells freshly isolated from decidual samples or conditionally cultured by TGFb stimulation.

FINDINGS

In preeclampsia, we documented elevated numbers of CD56⁺ CD3^- dNK cells in close proximity to Foxp3⁺ regulatory T (Treg) cells within the decidua. In vitro experiments using dNK cells from early gestation showed that dNK activation (IFNG, IL-8 and CD107a) can be downregulated by Treg cells. The expression of these markers by dNK cells was significantly lower in preeclampsia. We also observed a positive correlation between the expression of dNK activation receptors (NKp30 and NKG2D) and the expression of IFNG in specific dNK subsets. TGFb levels are increased in the decidua of preeclamptic pregnancies. We analyzed co-expression of activation (IFNG/IL-8/CD107a) and angiogenic (VEGF) markers in dNK cells. TGFb treatment reduced while blockade of TGFb increased co-expression of these markers.

INTERPRETATION

Our findings suggest that elevated decidual TGFb1 supresses the activation of specific subsets of dNK which in turn contributes to the uteroplacental pathology associated with the onset of preeclampsia.

Application of iTRAQ proteomics in identification of the differentially expressed proteins of placenta of pregnancy with preeclampsia

OBJECTIVE

To explore the differential protein profile of preeclampsia and identify its potential biomarker.

METHODS

Around 20 pregnant women with preeclampsia (preeclampsia group) and 20 normal-term pregnancy (normal group) were collected from 2017 to 2018 in the study. Total protein of placenta tissues was extracted, denaturized, deoxidized, and enzymolyzed. The sample was labeled with isobaric tags for relative and absolute quantitation (iTRAQ) and analyzed with mass spectrum to identify differentially expressed proteins.

RESULTS

There were 37 proteins, which were differentially expressed with significance (P < 0.05). Among them, 17 proteins were upregulated and 20 proteins were downregulated with significance in the placenta of preeclampsia group compared with control group, those proteins may have an induction or protection function during the development of preeclampsia.

CONCLUSION

iTRAQ technology can effectively screen the differentially expressed proteins in the placenta, which can effectively diagnose the preeclampsia during pregnancy.

The expression of serum sEGFR, sFlt-1, sEndoglin and PLGF in preeclampsia

The objective of this study was to investigate soluble epidermal growth factor receptor (sEGFR), soluble vascular endothelial growth factor receptor 1 (sFlt-1), soluble endoglin (sEndoglin) and placenta growth factor (PLGF) concentrations in normotensive, preterm and term preeclamptic pregnancies' serum and thus to specify the clinical utility of these biochemical markers in monitoring severity and intrauterine growth retardation of preterm preeclampsia. 172 pregnant women were divided into the following groups: preterm preeclampsia, preterm control, term preeclampsia and term control. Preterm preeclampsia patients were stratified with severe feature (n = 50) and without severe feature (n = 22). sEGFR, sEndoglin and PLGF were assessed using Luminex multiplex immunoassay, whilesFlt-1 was assessed using ELISA. sEGFR was significantly lower in preterm preeclampsia than matched control (p < 0.001) and mildly lower in term preeclampsia than matched control (p < 0.01). On contrary, sFlt-1 was significantly higher in preterm preeclampsia than matched control (p < 0.001) and mildly higher in term preeclampsia than matched control (p < 0.01). sFlt-1, sFlt-1/sEGFR and sFlt-1/PLGF were positively correlated with the severity of preterm preeclampsia (P < 0.001, R value ≥ 0.6), especially sFlt-1/sEGFR had the highest R value (R value = 0.711) among them. Furthermore, sEndoglin and the ratio of sEndoglin/sEGFR were associated with neonatal birth weight small for gestational age (SGA, n = 25) in preterm preeclampsia group.

CONCLUSIONS

The ratio of sFlt-1/sEGFR could be used as a novel candidate biochemical marker in monitoring the severity of preterm preeclampsia. sEndoglin and sEGFR may be involved in the pathogenesis of SGA in preterm preelampsia.

Serum protein marker panel for predicting preeclampsia

BACKGROUND

Preeclampsia is a multi-system disorder in pregnancy which has no effective treatment. The diagnosis of preeclampsia is based on clinical presentation and routine laboratory tests.

OBJECTIVE

This study aimed at identifying serum protein markers for diagnosis of preeclampsia and predicting its severe features.

STUDY DESIGN

In total, 172 pregnant women were enrolled in this study including 110 subjects with preeclampsia and 62 normotensive subjects. Eleven serum proteins (VEGF, sFlt-1, sEndoglin, PlGF, sEGFR, prolactin, PTX3, PAI-1, NGAL, IL-27, COX-2) were assessed using Luminex multiplex immunoassay and ELISA.

RESULTS

The levels of seven proteins (sFlt-1, VEGF, sEndoglin, sEGFR, PlGF, NGAL, COX-2) correlated with preeclampsia, and 4 proteins (VEGF, sEndoglin, PlGF, sEGFR) were identified as independent factors associated with preeclampsia. The levels of three proteins (sEndoglin, PTX3, sFlt-1) correlated with severe features of preeclampsia, and three variables (serum creatinine, platelet count and sEndoglin) were identified as independent factors in predicting severe features of preeclampsia.

CONCLUSIONS

A combination of serum protein markers (VEGF, sEndoglin, PlGF, sEGFR) and clinical variables (serum creatinine, platelet count and sEndoglin) could be used as analytical tool in diagnosis of preeclampsia and its severe features, respectively. Serum sEGFR, a novel biomarker in preeclampsia, may be involved in the pathogenesis of preeclampsia.

Proteomics Method to Identification of Protein Profiles in Exosomes

Exosomes are membrane-bound nanovesicles that transport molecular signals (e.g., proteins) between cells and are released from a wide range of cells, including the human placenta. Interestingly, the levels of exosomes present in maternal circulation are higher in preeclamptic pregnancies and their protein content profile change in response to the microenvironment milieu. Through the discovery of candidate biomarkers, mass spectrometry (MS)-based proteomics may provide a better understanding of the pathophysiology underlying pregnancy-associated disorders. With advances in sample preparation techniques, computational methodologies, and bioinformatics, MS-based proteomics have addressed the challenge of identifying and quantifying thousands of proteins and peptides from a variety of complex biological samples. Despite increasing interest in biomarker diagnostics, the complex nature of biological matrices (e.g., plasma) poses a challenge for candidate biomarker discovery. Here we describe a workflow to prepare exosomes for proteomic analysis.

Mechanisms of plasminogen activator inhibitor 1 action in stromal remodeling and related diseases

Plasminogen activator inhibitor type 1 (PAI-1) is the main physiologic inhibitor of fibrinolysis. However, it is also involved in many physiological processes such as extracellular matrix (ECM) proteolysis and remodeling, cell adhesion, motility, and apoptosis, angiogenesis, etc. The aim of the study was to summarize current knowledge and gain insights into the mechanisms of PAI-1 action in the processes of stromal remodeling and diseases with considerable matrix pathologies (atherosclerosis, tissue fibrosis, cancer metastasis, pregnancy related complications, etc). As a component of an early cellular response to injury, PAI-1 reacts with membrane surface proteins and participates in the initiation of intracellular signaling, specifically cytoskeletal reorganization and motility. Complexity of ECM homeostasis resides in varying relation of the plasminogen system components and other matrix constituents. Inflammatory mediators (transforming growth factor-β and interferon-γ) and hormones (angiotensin II) are in the close interdependent relation with PAI-1. Also, special attention is devoted to the role of increased PAI-1 concentrations due to the common 4G/5G polymorphism. Some of the novel mechanisms of ECM modification consider PAI-1 dependent stabilization of urokinase mediated cell adhesion, control of the vascular endothelial cadherin trafficking and interaction with endothelial cells proteasome, its relation to matrix metalloproteinase 2 and osteopontin, and oxidative inhibition by myeloperoxidase. Targeting and/or alteration of PAI-1 functions might bring benefit to the future therapeutic approaches in diseases where ECM undergoes substantial remodeling.

Consensus strategy in genes prioritization and combined bioinformatics analysis for preeclampsia pathogenesis

BACKGROUND

Preeclampsia is a multifactorial disease with unknown pathogenesis. Even when recent studies explored this disease using several bioinformatics tools, the main objective was not directed to pathogenesis. Additionally, consensus prioritization was proved to be highly efficient in the recognition of genes-disease association. However, not information is available about the consensus ability to early recognize genes directly involved in pathogenesis. Therefore our aim in this study is to apply several theoretical approaches to explore preeclampsia; specifically those genes directly involved in the pathogenesis.

METHODS

We firstly evaluated the consensus between 12 prioritization strategies to early recognize pathogenic genes related to preeclampsia. A communality analysis in the protein-protein interaction network of previously selected genes was done including further enrichment analysis. The enrichment analysis includes metabolic pathways as well as gene ontology. Microarray data was also collected and used in order to confirm our results or as a strategy to weight the previously enriched pathways.

RESULTS

The consensus prioritized gene list was rationally filtered to 476 genes using several criteria. The communality analysis showed an enrichment of communities connected with VEGF-signaling pathway. This pathway is also enriched considering the microarray data. Our result point to VEGF, FLT1 and KDR as relevant pathogenic genes, as well as those connected with NO metabolism.

CONCLUSION

Our results revealed that consensus strategy improve the detection and initial enrichment of pathogenic genes, at least in preeclampsia condition. Moreover the combination of the first percent of the prioritized genes with protein-protein interaction network followed by communality analysis reduces the gene space. This approach actually identifies well known genes related with pathogenesis. However, genes like HSP90, PAK2, CD247 and others included in the first 1% of the prioritized list need to be further explored in preeclampsia pathogenesis through experimental approaches.

Low-dose radiation modulates human mesenchymal stem cell proliferation through regulating CDK and Rb

Low-dose radiation (LDR) has been known to stimulate cell proliferation. The effect of LDR on human bone marrow mesenchymal stem cells (BMSCs), however, remains to be determined. The current study, therefore, aimed to investigate the effect of LDR on human BMSC proliferation and its mechanisms. To accomplish this, human BMSCs were isolated from ribs and cultured with or without exposition to LDR (75 mGy) for 24 h. Cell proliferation was assessed by MTT assay, the cytokines secreted by the BMSCs were quantified by ELISA, and the proteins associated with cell proliferation and cell cycle were evaluated by immunoblot analysis. BMSCs isolated from human ribs were capable of differentiating into osteoblasts and adipocytes. LDR stimulated human BMSC proliferation (0.580 ± 0.106 vs 0.419 ± 0.026 on day 4, P < 0.05; 0.794 ± 0.025 vs 0.689 ± 0.047 on day 7, P < 0.05) and increased S-phase proportion. LDR significantly enhanced the production of SCF, GM-CSF, and IL-11. Moreover, BMSCs modulated T-cell proliferation, and LDR further augmented the modulatory effect of BMSCs on T-cell proliferation. Cell cycle-associated proteins, such as Rb, CDK1, and CDC25B, appeared to mediate the stimulatory effect of LDR on BMSC proliferation. The findings of the current study indicate that physical stimulants, such as LDR, could be used for the large-scale expansion of human BMSCs, and thus may be used for MSC cellular therapy in clinic.

Expression profiling of maternal plasma and placenta microRNAs in preeclamptic pregnancies by microarray technology

Preeclampsia (PE) is one of the leading causes of maternal and fetal morbidity and mortality, occurring usually in the second half of pregnancy and affecting approximately 5-8% of pregnancies in the world. miRNAs play critical role in the regulation of placental development processes. We aimed to determine specific novel miRNAs for early diagnosis of preeclampsia which is one of the most dangerous pregnancy diseases. In this study 72 samples, maternal age 22 ≤ and ≤36, have been analyzed; maternal plasma and placental miRNAs were isolated from 18 severe preeclampsia (sPE) patients and 18 controls, respectively. Profiling of human miRNAs (1368 probe) was performed in samples with Agilent v16 microarrays for detection of the differences in miRNA expression between two groups. The results were validated by using TaqMan RT-qPCR method. The analysis indicated that 406 of these miRNAs in all placentas and 42 of these miRNAs in all maternal plasma were expressed. The relative expression analysis has shown that 12 miRNAs (p < 0.05 and >2-fold) in maternal plasma were differentially expressed in PE and control group. However, five miRNAs were validated by qRT-PCR. Once validated miRNAs have been searched in databases for their target genes and function, it has been shown that there are some preeclampsia related pathways as a target such as angiogenesis, cardiovascular, hypertension, placental abruption and preeclampsia disorders. Differentially expressed and validated plasma miRNAs might be used as notable biomarkers for non-invasive early diagnosis of preeclampsia and treatment of disease.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.