SERPINA1 Peptides in Urine as A Potential Marker of Preeclampsia Severity

Integrating bioinformatics and metabolomics to identify potential biomarkers of hypertensive nephropathy

Hypertensive nephropathy (HN), caused by long-term poorly controlled hypertension, is the second common cause of end-stage renal disease after diabetes mellitus, but the pathogenesis of HN is unclear. The purpose of this study was to identify the biological pathways involved in the progression of HN and bile acid (BA)-related biomarkers, and to analyze the role of bile acids in HN. Download gene microarray data from Gene Expression Omnibus. Differentially expressed genes (DEGs) associated with HN were identified, and then DEGs were subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis. A protein-protein interaction (PPI) network was established using DEGs to identify BA-related hub genes in combination with bile acid identical targets. An animal model of early hypertensive nephropathy was established using SHR and the concentrations of 39 bile acids were measured quantitatively in the renal cortex to screen for significantly different concentrations and to analyze the correlation between bile acid concentrations and blood pressure. A total of 398 DEGs were screened. The results of enrichment analysis identified multiple biological pathways associated with hypertension, nephropathy and bile acids. Combining PPI network and bile acid-related targets, three BA-related hub genes (APOE, ALB, SERPINA1) were identified. Quantitative analysis of bile acids revealed significant differences in the concentrations of seven bile acids (DCA, CDCA, UDCA, UCA, CA, TDCA, TCDCA). The concentrations of these bile acids showed a positive correlation with blood pressure values in SHR, with CA, DCA and TDCA showing a stronger correlation and specificity with blood pressure in SHR. Three BA-related hub genes (APOE, ALB, SERPINA1) may be involved in the early stages of HN. The concentrations of multiple bile acids were significantly elevated in the early stages of HN, with CA, DCA and TDCA being more correlated and specific with blood pressure and having higher diagnostic value. These BA-related hub genes and BAs may be involved in disease progression in the early stages of HN.

Seasonal Influences on Human Placental Transcriptomes Associated with Spontaneous Preterm Birth

Demographic studies have revealed a strong association between exposure to high ambient temperatures during pregnancy and increased risks of preterm birth (PTB). The mechanism underlying this association is unclear, but it is plausible that altered placental function may contribute to it. In this study, we conducted differential gene expression analysis, gene set enrichment analysis (GSEA), and gene ontology (GO) analysis on bulk RNA-seq data from human placentas delivered at term and preterm during the warmer months compared to placentas delivered at term and preterm during the colder months in the UK. We detected 48 differentially expressed genes in preterm placentas delivered during the warmer months compared to preterm placentas delivered during the colder months, the majority of which were inflammatory cytokines and chemokines, including SERPINA1, IL1B, CCL3, CCL3L3, CCL4, CCL4L2, CCL20, and CXCL8. The GSEA positively enriched 17 signalling pathways, including the NF-κB, IL17, Toll-like receptor, and chemokine signalling pathways in preterm placentas delivered during warmer months. These results were not observed in the placentas delivered at term during the same times of the year. The GO analysis revealed several enhanced biological processes, including neutrophil, granulocyte, monocyte, and lymphocyte chemotaxis, as well as inflammatory and humoral immune responses in preterm placentas, but not in placentas delivered at term in the summer. We conclude that maternal exposure to warm environmental temperatures during pregnancy likely alters the placental transcriptomes towards inflammation and immune regulation, potentially leading to PTB.

Urinary biomarkers of preeclampsia: An update

Preeclampsia (PE), a pregnancy-related syndrome, has motivated extensive research to understand its pathophysiology and develop early diagnostic methods. 'Omic' technologies, focusing on genes, mRNA, proteins, and metabolites, have revolutionized biological system studies. Urine emerges as an ideal non-invasive specimen for omics analysis, offering accessibility, easy collection, and stability, making it valuable for identifying biomarkers. A comprehensive exploration of urinary omics in preeclampsia is discussed in this review. Proteomic studies identified biomarkers such as SERPINA-1 and uromodulin, showing promise for early diagnosis and severity assessment. Metabolomic analyses revealed alterations in metabolites like glycine and hippurate, providing insights into molecular mechanisms underlying PE. Challenges include methodological inconsistencies and the need for standardized protocols. Urinary omics technologies have significantly advanced our understanding of PE pathophysiology and hold promise for improved diagnosis and management. Biomarkers identified through these approaches offer potential for early detection, severity stratification, and elucidation of underlying mechanisms.

Alpha-1-antitrypsin as novel substrate for S. aureus' Spl proteases - implications for virulence

Background

The serine protease like (Spl) proteases of Staphylococcus aureus are a family of six proteases whose function and impact on virulence are poorly understood. Here we propose alpha-1-antitrypsin (AAT), an important immunomodulatory serine protease inhibitor as target of SplD, E and F. AAT is an acute phase protein, interacting with many proteases and crucial for prevention of excess tissue damage by neutrophil elastase during the innate immune response to infections.

Methods

We used MALDI-TOF-MS to identify the cleavage site of Spl proteases within AAT's reactive center loop (RCL) and LC-MS/MS to quantify the resulting peptide cleavage product in in vitro digestions of AAT and heterologous expressed proteases or culture supernatants from different S. aureus strains. We further confirmed proteolytic cleavage and formation of a covalent complex with Western Blots, investigated AAT's inhibitory potential against Spls and examined the NETosis inhibitory activity of AAT-Spl-digestions.

Results

SplD, E and F, but not A or B, cleave AAT in its RCL, resulting in the release of a peptide consisting of AAT's C-terminal 36 amino acids (C36). Synthetic C36, as well as AAT-SplD/E/F-digestions exhibit NETosis inhibition. Only SplE, but not D or F, was partly inhibited by AAT, forming a covalent complex.

Conclusion

We unraveled a new virulence trait of S. aureus, where SplD/E/F cleave and inactivate AAT while the cleavage product C36 inhibits NETosis.

First-Trimester Preeclampsia-Induced Disturbance in Maternal Blood Serum Proteome: A Pilot Study

Preeclampsia (PE) is a complex and multifaceted obstetric syndrome characterized by several distinct molecular subtypes. It complicates up to 5% of pregnancies and significantly contributes to maternal and newborn morbidity, thereby diminishing the long-term quality of life for affected women. Due to the widespread dissatisfaction with the effectiveness of existing approaches for assessing PE risk, there is a pressing need for ongoing research to identify newer, more accurate predictors. This study aimed to investigate early changes in the maternal serum proteome and associated signaling pathways. The levels of 125 maternal serum proteins at 11-13 weeks of gestation were quantified using liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM MS) with the BAK-125 kit. Ten serum proteins emerged as potential early markers for PE: Apolipoprotein M (APOM), Complement C1q subcomponent subunit B (C1QB), Lysozyme (LYZ), Prothrombin (F2), Albumin (ALB), Zinc-alpha-2-glycoprotein (AZGP1), Tenascin-X (TNXB), Alpha-1-antitrypsin (SERPINA1), Attractin (ATRN), and Apolipoprotein A-IV (APOA4). Notably, nine of these proteins have previously been associated with PE in prior research, underscoring the consistency and reliability of our findings. These proteins play key roles in critical molecular processes, including complement and coagulation cascades, platelet activation, and insulin-like growth factor pathways. To improve the early prediction of PE, a highly effective Support Vector Machine (SVM) model was developed, analyzing 19 maternal serum proteins from the first trimester. This model achieved an area under the curve (AUC) of 0.91, with 87% sensitivity and 95% specificity, and a hazard ratio (HR) of 13.5 (4.6-40.8) with p < 0.001. These findings demonstrate that serum protein-based SVM models possess significantly higher predictive power compared to the routine first-trimester screening test, highlighting their superior utility in the early detection and risk stratification of PE.

Comparative peptidomics analysis of preeclamptic placenta and the identification of a novel bioactive SERPINA1 C-terminal peptide

Preeclampsia (PE) is a life-threatening disease that severely harms pregnant women and infants' health but has a poorly understood etiology. Peptidomics can supply important information about the occurrence of diseases. However, application of peptidomics in preeclamptic placentas has never been reported. We conducted a comparative peptidomics analysis of PE placentas and performed bio-informatics analysis on differentially expressed peptides. Effects of differential peptide 405SPLFMGKVVNPTQK418 on the behaviors of trophoblasts and angiogenesis were assessed by CCK8, transwell assays, and tube network formation assays. And we also confirmed the role of peptide in the zebrafish xenograft model. A total of 3582 peptide were identified. 48 peptides were differentially expressed. Bioinformatics analysis indicated that precursor proteins of these differentially expressed peptides correlate with "complement and coagulation cascades," and "platelet activation" pathways. Of the 48 differential peptides, we found that peptide 405SPLFMGKVVNPTQK418 can significantly increase proliferation, migration of trophoblasts and stimulate angiogenesis of HUVECs in vitro and zebrafish model. These findings suggest peptidomes can aid in understanding the pathogenesis of PE more comprehensively. Peptide 405SPLFMGKVVNPTQK418 can be novel target and strategy to alleviate the condition of preeclampsia.

Recent progress in mass spectrometry-based urinary proteomics

Serum or plasma is frequently utilized in biomedical research; however, its application is impeded by the requirement for invasive sample collection. The non-invasive nature of urine collection makes it an attractive alternative for disease characterization and biomarker discovery. Mass spectrometry-based protein profiling of urine has led to the discovery of several disease-associated biomarkers. Proteomic analysis of urine has not only been applied to disorders of the kidney and urinary bladder but also to conditions affecting distant organs because proteins excreted in the urine originate from multiple organs. This review provides a progress update on urinary proteomics carried out over the past decade. Studies summarized in this review have expanded the catalog of proteins detected in the urine in a variety of clinical conditions. The wide range of applications of urine analysis-from characterizing diseases to discovering predictive, diagnostic and prognostic markers-continues to drive investigations of the urinary proteome.

Protein Misfolding in Pregnancy: Current Insights, Potential Mechanisms, and Implications for the Pathogenesis of Preeclampsia

Protein misfolding disorders are a group of diseases characterized by supra-physiologic accumulation and aggregation of pathogenic proteoforms resulting from improper protein folding and/or insufficiency in clearance mechanisms. Although these processes have been historically linked to neurodegenerative disorders, such as Alzheimer's disease, evidence linking protein misfolding to other pathologies continues to emerge. Indeed, the deposition of toxic protein aggregates in the form of oligomers or large amyloid fibrils has been linked to type 2 diabetes, various types of cancer, and, in more recent years, to preeclampsia, a life-threatening pregnancy-specific disorder. While extensive physiological mechanisms are in place to maintain proteostasis, processes, such as aging, genetic factors, or environmental stress in the form of hypoxia, nutrient deprivation or xenobiotic exposures can induce failure in these systems. As such, pregnancy, a natural physical state that already places the maternal body under significant physiological stress, creates an environment with a lower threshold for aberrant aggregation. In this review, we set out to discuss current evidence of protein misfolding in pregnancy and potential mechanisms supporting a key role for this process in preeclampsia pathogenesis. Improving our understanding of this emerging pathophysiological process in preeclampsia can lead to vital discoveries that can be harnessed to create better diagnoses and treatment modalities for the disorder.

Proximal tubule cells in blood and urine as potential biomarkers for kidney disease biopsy

Early diagnosis and treatment are crucial for managing kidney disease, yet there remains a need to further explore pathological mechanisms and develop minimally invasive diagnostic methods. In this study, we employed single-cell RNA sequencing (scRNA-seq) to assess the cellular heterogeneity of kidney diseases. We analyzed gene expression profiles from renal tissue, peripheral blood mononuclear cells (PBMCs), and urine of four patients with nephritis. Our findings identified 12 distinct cell subsets in renal tissues and leukocytes. These subsets encompassed fibroblast cells, mesangial cells, epithelial cells, proximal tubule cells (PTCs), and six immune cell types: CD8+ T cells, macrophages, natural killer cells, dendritic cells, B cells, and neutrophils. Interestingly, PTCs were present in both PBMCs and urine samples but absent in healthy blood samples. Furthermore, several populations of fibroblast cells, mesangial cells, and PTCs exhibited pro-inflammatory or pro-apoptotic behaviors. Our gene expression analysis highlighted the critical role of inflammatory PTCs and fibroblasts in nephritis development and progression. These cells showed high expression of pro-inflammatory genes, which could have chemotactic and activating effect on neutrophils. This was substantiated by the widespread in these cells. Notably, the gene expression profiles of inflammatory PTCs in PBMCs, urine, and kidney tissues had high similarity. This suggests that PTCs in urine and PBMCs hold significant potential as alternative markers to invasive kidney biopsies.

Conceiving complexity: Biological mechanisms underpinning the lasting effect of pregnancy on multiple sclerosis outcomes

Multiple sclerosis (MS) is an autoimmune, demyelinating disease with the highest incidence in women of childbearing age. The effect of pregnancy on disease activity and progression is a primary concern for women with MS and their clinical teams. It is well established that inflammatory disease activity is naturally suppressed during pregnancy, followed by an increase postpartum. However, the long-term effect of pregnancy on disease progression is less understood. Having had a pregnancy before MS onset has been associated with an older age at first demyelinating event, an average delay of 3.4 years. After MS onset, there is conflicting evidence about the impact of pregnancy on long-term outcomes. The study with the longest follow-up to date showed that pregnancy was associated with a 0.36-point lower disability score after 10-years of disease in 1830 women. Understanding the biological mechanism by which pregnancy induces long-term beneficial effects on MS outcomes could provide mechanistic insights into the elusive determinants of secondary progression. Here, we review potential biological processes underlying this effect, including evidence that acute sex hormone exposure induces lasting changes to neurobiological and DNA methylation patterns, and how sustained methylation changes in immune cells can alter immune composition and function long-term.

Integrated proteome sequencing, bulk RNA sequencing and single-cell RNA sequencing to identify potential biomarkers in different grades of intervertebral disc degeneration

Low back pain (LBP) is a prevalent health problem worldwide that affects over 80% of adults during their lifetime. Intervertebral disc degeneration (IDD) is a well-recognized leading cause of LBP. IDD is classified into five grades according to the Pfirrmann classification system. The purpose of this study was to identify potential biomarkers in different IDD grades through an integrated analysis of proteome sequencing (PRO-seq), bulk RNA sequencing (bRNA-seq) and single-cell RNA sequencing (scRNA-seq) data. Eight cases of grade I-IV IDD were obtained. Grades I and II were considered non-degenerative discs (relatively normal), whereas grades III and IV were considered degenerative discs. PRO-seq analysis was performed to identify differentially expressed proteins (DEPs) in various IDD grades. Variation analysis was performed on bRNA-seq data to differentiate expressed genes (DEGs) in normal and degenerated discs. In addition, scRNA-seq was performed to validate DEGs in degenerated and non-degenerated nucleus pulposus (NP). Machine learning (ML) algorithms were used to screen hub genes. The receiver operating characteristic (ROC) curve was used to validate the efficiency of the screened hub genes to predict IDD. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to analyze function enrichment and signaling pathways. Protein-protein interaction (PPI) network was used to prioritize disease-related proteins. SERPINA1, ORM2, FGG and COL1A1 were identified through PRO-seq as the hub proteins involved in regulating IDD. ML algorithms selected ten hub genes, including IBSP, COL6A2, MMP2, SERPINA1, ACAN, FBLN7, LAMB2, TTLL7, COL9A3, and THBS4 in bRNA-seq. Since serine protease inhibitor clade A member 1 (SERPINA1) was the only common gene, its accuracy in degenerated and non-degenerated NP cells was validated using scRNA-seq. Then, the rat degeneration model of caudal vertebra was established. The expression of SERPINA1 and ORM2 was detected using immunohistochemical staining of human and rat intervertebral discs. The results showed that SERPINA1 was poorly expressed in the degenerative group. We further explored the potential function of SERPINA1 by Gene Set Enrichment Analysis (GSEA) and cell-cell communication. Therefore, SERPINA1 can be used as a biomarker to regulate or predict the progress of disc degeneration.

Screening and functional analysis of the differential peptides from the placenta of patients with healthy pregnancy and preeclampsia using placental peptidome

Molecular peptides play an extensive range of functions in the human body. However, no previous study has performed placental peptidome profiling. In the present study, 3,941 peptides from human placental tissues were identified using peptidomics. Compared to healthy pregnant women, there were 87 and 129 differentially expressed peptides (DEPs) in the mild and severe preeclampsia groups, respectively. In the mild PE group, 55 and 34 DEPs had high and low expressions, respectively. In comparison, in the severe PE group, 82 and 47 DEPs had high and low expressions, respectively. Functional analysis of the precursor proteins of DEPs by gene ontology suggested that they are primarily involved in focal adhesion, extracellular matrix-receptor interaction, tight junction, and extracellular matrix. Network analysis using ingenuity pathway analysis software showed that the precursor proteins of DEPs were primarily related to the transforming growth factor-β (TGF-β)/Smad signaling pathway. Further molecular docking experiments showed that the AASAKKKNKKGKTISL peptide (placenta-derived peptide, PDP) derived from the precursor protein IF4B could bind to TGF-β1. Therefore, our preliminary results suggest that the actions of PDP may be mediated through the TGF-β1/Smad signaling pathway. Our results demonstrate that the placental bioactive peptides may regulate the placental function during PE progression.

Platelet mitochondrial membrane depolarization reflects disease severity in patients with preeclampsia

BACKGROUND

Thrombocytopenia is a feared complication of preeclampsia (PE) that can additionally complicate the disease course and that carries a poor prognosis. The disease mechanisms of PE on a platelet level are poorly understood and only few platelet-based markers have been investigated. In sepsis, platelet mitochondrial membrane depolarization, a sensitive and early indicator of mitochondrial dysfunction and platelet cell death, correlates with disease severity and outcome as shown in previous studies. The aim of this study was to investigate platelet mitochondrial membrane potential (Mmp-Index) by flow-cytometry in patients with preeclampsia compared to controls and to assess its value in correlation with disease severity of PE and during follow-up after delivery.

METHODS

In this prospective translational case-control study, platelet Mmp-Index was measured in PE (n = 16) by flow cytometry in living platelets in simultaneous comparison to healthy pregnant (n = 32) and non-pregnant controls (n = 16) and was individually reassessed after delivery to investigate recovery of platelet mitochondrial function. Subgroup analysis of patients with severe and non-severe PE was performed. Six patients with isolated gestational hypertension were also included for comparative analysis.

RESULTS

Platelet Mmp-Index in patients with symptomatic preeclampsia (Mmp-Index non-severe PE 0.72 ([0.591; 0.861]; p = 0.002) was significantly reduced compared to healthy pregnant controls (Mmp-Index 0.97 [0.795; 1.117]) and even more pronounced in patients with severe PE (n = 6) (Mmp-Index severe PE 0.542 [0.361; 0.623]; p = 0.03). In the severe PE group, complementary measurements of platelet Annexin V- and CD62 (P-Selectin) surface expression showed apoptosis of platelet populations in the majority of patients. Platelet Mmp normalized after delivery within few days. Patients with isolated gestational hypertension showed normal Mmp-Index values.

CONCLUSIONS

This study shows for the first time that platelet Mmp-Index is a quantifiable, easy-to-measure intracellular marker of platelet mitochondrial function in vital cells that reflects disease severity of preeclampsia. For future investigations, platelet Mmp may serve as a prognostic marker that may aid clinical risk stratification and adds novel information on potential mechanisms for thrombocytopenia in preeclampsia.

Human placental proteomics and exon variant studies link AAT/SERPINA1 with spontaneous preterm birth

BACKGROUND

Preterm birth is defined as live birth before 37 completed weeks of pregnancy, and it is a major problem worldwide. The molecular mechanisms that lead to onset of spontaneous preterm birth are incompletely understood. Prediction and evaluation of the risk of preterm birth is challenging as there is a lack of accurate biomarkers. In this study, our aim was to identify placental proteins that associate with spontaneous preterm birth.

METHODS

We analyzed the proteomes from placentas to identify proteins that associate with both gestational age and spontaneous labor. Next, rare and potentially damaging gene variants of the identified protein candidates were sought for from our whole exome sequencing data. Further experiments we performed on placental samples and placenta-associated cells to explore the location and function of the spontaneous preterm labor-associated proteins in placentas.

RESULTS

Exome sequencing data revealed rare damaging variants in SERPINA1 in families with recurrent spontaneous preterm deliveries. Protein and mRNA levels of alpha-1 antitrypsin/SERPINA1 from the maternal side of the placenta were downregulated in spontaneous preterm births. Alpha-1 antitrypsin was expressed by villous trophoblasts in the placenta, and immunoelectron microscopy showed localization in decidual fibrinoid deposits in association with specific extracellular proteins. siRNA knockdown in trophoblast-derived HTR8/SVneo cells revealed that SERPINA1 had a marked effect on regulation of the actin cytoskeleton pathway, Slit-Robo signaling, and extracellular matrix organization.

CONCLUSIONS

Alpha-1 antitrypsin is a protease inhibitor. We propose that loss of the protease inhibition effects of alpha-1 antitrypsin renders structures critical to maintaining pregnancy susceptible to proteases and inflammatory activation. This may lead to spontaneous premature birth.

Towards unveiling the nature of short SERPINA1 transcripts: Avoiding the main ORF control to translate alpha1-antitrypsin C-terminal peptides

Alternative ORFs in-frame with the known genes are challenging to reveal. Yet they may contribute significantly to proteome diversity. Here we focused on the individual expression of the SERPINA1 gene exon 5 leading to direct translation of alpha1-antitrypsin (AAT) C-terminal peptides. The discovery of alternative ways for their production may expand the current understanding of the serpin gene's functioning. We detected short transcripts expressed primarily in hepatocytes. We identified four variants of hepatocyte-specific SERPINA1 short transcripts and individually probed their potential to be translated in living cells. The long mRNA gave the full-length AAT-eGFP fusion, while in case of short transcripts we deduced four active SERPINA1 in-frame alternative ORFs encoding 10, 21, 153 and 169 amino acids AAT C-terminal oligo- and polypeptides. Unlike secretory AAT-eGFP fusion exhibiting classical AAT behavior, truncated AAT-fusions differ by intracellular retention and nuclear enrichment. Immunofluorescence on the endogenous AAT C-terminal epitope showed its accumulation in the cell nucleoli, indicating that short transcripts may be translated in vivo. FANTOM5 CAGE data on SERPINA1 suggest that short transcripts originate from the post-transcriptional cleavage of the spliced mRNA, initiated mainly from the hepatocyte-specific promoter. CONCLUSION: Short SERPINA1 transcripts may represent a source for the direct synthesis of AAT C-terminal peptides with properties uncommon to AAT.

Pathogenesis of Pregnancy-Related Complications 1.0 and 2.0

These Special Issue IJMS were dedicated to the major complications responsible for maternal and perinatal morbidity and mortality, such as gestational hypertension (GH), preeclampsia (PE), fetal growth restriction (FGR), gestational diabetes mellitus (GDM), preterm birth, and chronic venous disease [...]

Alpha 1 Antitrypsin Regulates Trophoblast Syncytialization and Inflammatory Factor Expression

The serine protease inhibitor alpha1-antitrypsin (A1AT) may possess protective functions of impaired organs in a manner independent of its protease inhibitor activity. A1AT expression has been shown to fluctuate in patients with pregnancy-induced hypertension, which suggests that A1AT may play a role in the syncytialization of villous trophoblasts. A1AT expression was knocked down in primary trophoblasts. RNA was extracted from these cells and subjected to RNA-sequencing analysis to determine the levels of expression of markers of syncytialization and inflammation. In addition, A1AT protein was localized in trophoblastic cells in placental tissues. Knockdown of A1AT upregulated the expression of FOSL1 and markers of syncytialization, as well as cell fusion, whereas overexpression of A1AT had the opposite effects. FOSL1 overexpression stimulated syncytialization, similar to the effects of A1AT knock down. Inhibitors of p38MAPK and JNK reduce the expression of inflammatory factors, whereas a p38MAPK inhibitor suppressed FOSL1 expression. Collectively, these findings indicated A1AT may negatively regulate inflammatory responses by controlling the activation of p38MAPK and JNK, and that p38MAPK mediates trophoblast syncytialization by altering FOSL1 expression. Therefore, a dysfunction in A1AT could be responsible for abnormal placental formation and pregnancy-associated disorders.

Proteomic Analysis of Maternal Urine for the Early Detection of Preeclampsia and Fetal Growth Restriction

Background: To explore the use of maternal urine proteome for the identification of preeclampsia biomarkers. Methods: Maternal urine samples from women with and without preeclampsia were used for protein discovery followed by a validation study. The targeted proteins of interest were then measured in urine samples collected at 20–24 and 30–34 weeks among nine women who developed preeclampsia, one woman with fetal growth restriction, and 20 women with uncomplicated pregnancies from a longitudinal study. Protein identification and quantification was obtained using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Results: Among the 1108 urine proteins quantified in the discovery study, 21 were upregulated in preeclampsia and selected for validation. Nineteen (90%) proteins were confirmed as upregulated in preeclampsia cases. Among them, two proteins, ceruloplasmin and serpin A7, were upregulated at 20–24 weeks and 30–34 weeks of gestation (p < 0.05) in cases of preeclampsia, and could have served to identify 60% of women who subsequently developed preeclampsia and/or fetal growth restriction at 20–24 weeks of gestation, and 78% at 30–34 weeks, for a false-positive rate of 10%. Conclusions: Proteomic profiling of maternal urine can differentiate women with and without preeclampsia. Several proteins including ceruloplasmin and serpin A7 are upregulated in maternal urine before the diagnosis of preeclampsia and potentially fetal growth restriction.

A novel peptide promotes human trophoblast proliferation and migration through PI3K/Akt/mTOR signaling pathway

Background

Preeclampsia (PE) is a complex pregnancy-related disease that endangers the safety of maternal and fetal. The purpose of this study is to reveal the pathogenesis of preeclampsia and discover new predictors from the perspective of peptidomics. The umbilical cord blood of PE and control group was analyzed by peptidomics. A peptide named Regulation of Proliferation Process in Preeclampsia (ROPPIP) was screened out to explore its role in the proliferation, migration and apoptosis of trophoblast cells in preeclampsia.

Methods

We compared and analyzed the umbilical cord blood of patients with PE and normal pregnant women using liquid chromatography-tandem mass spectrometry (LC-MS). hTR-8/Svneo cells cultured in vitro were divided into ROPPIP group and a disordered peptide group as control. Cell Counting Kit-8 (CCK-8) assay, flow cytometry, Transwell chamber assays and western blot analysis were performed to detect cell proliferation, invasion, migration and apoptosis, in addition to the expression of Matrix metalloproteinase-2 (MMP2), nuclear associated antigen Ki67, B-cell lymphoma-2 (Bcl2), Caspase 3, and β-actin protein.

Results

We identified 133 differential peptides. Of these, 51 were up-regulated while 82 were down-regulated. the polypeptide SFGVRMATASPTDGNV with low differential expression in the serum of PE patients was selected for the study, we named the polypeptide as Regulation of Proliferation Process in PE (ROPPIP). The experiment shows that ROPPIP can up-regulate the expression levels of MMP2, Ki67, and Bcl2 in HTR-8/Svneo cells, down-regulate the expression of caspase-3, promote the proliferation and migration of HTR-8/Svneo cells and inhibit the apoptosis induced by cisplatin, the activation of the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway may be associated with the function of ROPPIP.

Conclusions

ROPPIP promotes HTR-8/Svneo cells migration and proliferation, and inhibits apoptosis, by regulating the activation of the PI3K/AKT/mTOR signaling pathway.

Alpha-1 Antitrypsin-Induced Endoplasmic Reticulum Stress Promotes Invasion by Extravillous Trophoblasts

Alpha-1 antitrypsin (A1AT) is a glycoprotein that has been shown to protect tissues from proteolytic damage under various inflammatory conditions. Several studies show that A1AT may be associated with pre-eclampsia. However, the role of A1AT expression in placental physiology is not fully understood. In the present study, we aim to characterize the expression and function of placental A1AT. A1AT knockdown is found to reduce the expression of the serine protease HTRA1 in a trophoblast cell line. In addition, A1AT overexpression (A1AT-OE) increases the expression of HTRA1, IL6, CXCL8, and several markers of endoplasmic reticulum (ER) stress. Treatment with tunicamycin or thapsigargin, which induces ER stress, increases HTRA1 expression. Furthermore, immunohistochemistry reveals that HTRA1 is expressed in trophoblasts and the endometrial decidual cells of human placentas. An invasion assay shows that A1AT and HTRA1 stimulate cell invasion, but treatment with the ER stress inhibitors reduces the expression of HTRA1 and ER stress markers and prevents cell invasion in A1AT-OE trophoblasts. These results suggest that endogenous A1AT regulates inflammatory cytokine expression and HTRA1-induced trophoblast invasion via the induction of ER stress. It is concluded that an imbalance in the functional link between A1AT and ER stress at the maternal-fetal interface might cause abnormal placental development.

Quantitative proteomics-based analyses performed on pre-eclampsia samples in the 2004-2020 period: a systematic review

BACKGROUND

Quantitative proteomics is an invaluable tool in biomedicine for the massive comparative analysis of protein component of complex biological samples. In the last two decades, this technique has been used to describe proteins potentially involved in the pathophysiological mechanisms of preeclampsia as well as to identify protein biomarkers that could be used with diagnostic/prognostic purposes in pre-eclampsia.

RESULTS

We have done a systematic review of all proteomics-based papers describing differentially expressed proteins in this disease. Searching Pubmed with the terms pre-eclampsia and proteomics, restricted to the Title/Abstract and to MeSH fields, and following manual curation of the original list, retrieved 69 original articles corresponding to the 2004-2020 period. We have only considered those results based on quantitative, unbiased proteomics studies conducted in a controlled manner on a cohort of control and pre-eclamptic individuals. The sources of biological material used were serum/plasma (n = 32), placenta (n = 23), urine (n = 9), cerebrospinal fluid (n = 2), amniotic fluid (n = 2) and decidual tissue (n = 1). Overall results were filtered based on two complementary criteria. First, we have only accounted all those proteins described in at least two (urine), three (placenta) and four (serum/plasma) independent studies. Secondly, we considered the consistency of the quantitative data, that is, inter-study agreement in the protein abundance control/pre-eclamptic ratio. The total number of differential proteins in serum/plasma (n = 559), placenta (n = 912), urine (n = 132) and other sources of biological material (n = 26), reached 1631 proteins. Data were highly complementary among studies, resulting from differences on biological sources, sampling strategies, patient stratification, quantitative proteomic analysis methods and statistical data analysis. Therefore, stringent filtering was applied to end up with a cluster of 18, 29 and 16 proteins consistently regulated in pre-eclampsia in placenta, serum/plasma and urine, respectively. The systematic collection, standardization and evaluation of the results, using diverse filtering criteria, provided a panel of 63 proteins whose levels are consistently modified in the context of pre-eclampsia.

Differential Diagnosis of Preeclampsia Based on Urine Peptidome Features Revealed by High Resolution Mass Spectrometry

Preeclampsia (PE) is a severe pregnancy complication, which may be considered as a systemic response in the second half of pregnancy to physiological failures in the first trimester, and can lead to very serious consequences for the health of the mother and fetus. Since PE is often associated with proteinuria, urine proteomic assays may represent a powerful tool for timely diagnostics and appropriate management. High resolution mass spectrometry was applied for peptidome analysis of 127 urine samples of pregnant women with various hypertensive complications: normotensive controls (n = 17), chronic hypertension (n = 16), gestational hypertension (n = 15), mild PE (n = 25), severe PE (n = 25), and 29 patients with complicated diagnoses. Analysis revealed 3869 peptides, which mostly belong to 116 groups with overlapping sequences. A panel of 22 marker peptide groups reliably differentiating PE was created by multivariate statistics, and included 15 collagen groups (from COL1A1, COL3A1, COL2A1, COL4A4, COL5A1, and COL8A1), and single loci from alpha-1-antitrypsin, fibrinogen, membrane-associated progesterone receptor component 1, insulin, EMI domain-containing protein 1, lysine-specific demethylase 6B, and alpha-2-HS-glycoprotein each. ROC analysis of the created model resulted in 88% sensitivity, 96.8% specificity, and receiver operating characteristic curve (AUC) = 0.947. Obtained results confirm the high diagnostic potential of urinary peptidome profiling for pregnancy hypertensive disorders diagnostics.