Augmented trophoblast cell death in preeclampsia can proceed via ceramide-mediated necroptosis

Apoptotic and non-apoptotic roles of caspases in placenta physiology and pathology

Caspases, a family of cysteine proteases, are pivotal regulators of apoptosis, the tightly controlled cell death process crucial for eliminating excessive or unnecessary cells during development, including placental development. Collecting research has unveiled the multifaceted roles of caspases in the placenta, extending beyond apoptosis. Apart from their involvement in placental tissue remodeling via apoptosis, caspases actively participate in essential regulatory processes, such as trophoblast fusion and differentiation, significantly influencing placental growth and functionality. In addition, growing evidence indicates an elevation in caspase activity under pathological conditions like pre-eclampsia (PE) and intrauterine growth restriction (IUGR), leading to excessive cell death as well as inflammation. Drawing from advancements in caspase research and placental development under both normal and abnormal conditions, we examine the significance of caspases in both cell death (apoptosis) and non-cell death-related processes within the placenta. We also discuss potential therapeutics targeting caspase-related pathways for placenta disorders.

The regulated cell death at the maternal-fetal interface: beneficial or detrimental?

Regulated cell death (RCD) plays a fundamental role in placental development and tissue homeostasis. Placental development relies upon effective implantation and invasion of the maternal decidua by the trophoblast and an immune tolerant environment maintained by various cells at the maternal-fetal interface. Although cell death in the placenta can affect fetal development and even cause pregnancy-related diseases, accumulating evidence has revealed that several regulated cell death were found at the maternal-fetal interface under physiological or pathological conditions, the exact types of cell death and the precise molecular mechanisms remain elusive. In this review, we summarized the apoptosis, necroptosis and autophagy play both promoting and inhibiting roles in the differentiation, invasion of trophoblast, remodeling of the uterine spiral artery and decidualization, whereas ferroptosis and pyroptosis have adverse effects. RCD serves as a mode of communication between different cells to better maintain the maternal-fetal interface microenvironment. Maintaining the balance of RCD at the maternal-fetal interface is of utmost importance for the development of the placenta, establishment of an immune microenvironment, and prevention of pregnancy disorders. In addition, we also revealed an association between abnormal expression of key molecules in different types of RCD and pregnancy-related diseases, which may yield significant insights into the pathogenesis and treatment of pregnancy-related complications.

Lipid profile of circulating placental extracellular vesicles during pregnancy identifies foetal growth restriction risk

Small-for-gestational age (SGA) neonates exhibit increased perinatal morbidity and mortality, and a greater risk of developing chronic diseases in adulthood. Currently, no effective maternal blood-based screening methods for determining SGA risk are available. We used a high-resolution MS/MSALL shotgun lipidomic approach to explore the lipid profiles of small extracellular vesicles (sEV) released from the placenta into the circulation of pregnant individuals. Samples were acquired from 195 normal and 41 SGA pregnancies. Lipid profiles were determined serially across pregnancy. We identified specific lipid signatures of placental sEVs that define the trajectory of a normal pregnancy and their changes occurring in relation to maternal characteristics (parity and ethnicity) and birthweight centile. We constructed a multivariate model demonstrating that specific lipid features of circulating placental sEVs, particularly during early gestation, are highly predictive of SGA infants. Lipidomic-based biomarker development promises to improve the early detection of pregnancies at risk of developing SGA, an unmet clinical need in obstetrics.

The anti-cancer drug candidate CBL0137 induced necroptosis via forming left-handed Z-DNA and its binding protein ZBP1 in liver cells

CBL0137, a promising small molecular anti-cancer drug candidate, has been found to effectively induce apoptosis via activating p53 and suppressing nuclear factor-kappa B (NF-κB). However, it is still not clear whether CBL0137 can induce necroptosis in liver cancer; and if so, what is the underlying molecular mechanism. Here we found that CBL0137 could significantly induce left-handed double helix structure Z-DNA formation in HepG2 cells as shown by Z-DNA specific antibody assay, which was further confirmed by observing the expression of Z-DNA binding protein 1 (ZBP1) and adenosine deaminase acting on RNA 1 (ADAR1). Interestingly, we found that caspase inhibition significantly promoted CBL0137-induced necroptosis, which was further supported with the increase of the late apoptosis and necrosis assessed by the flow cytometry. Furthermore, we found that CBL0137 can also induce the expression of the three necroptosis-related proteins: receptor interacting serine/threonine kinase 1 (RIPK1), receptor interacting serine/threonine kinase 3 (RIPK3), and mixed lineage kinase domain-like (MLKL). Taken together, it was assumed that CBL0137-indued necroptosis in liver cells was due to induction of Z-DNA and ZBP1, which activated RIPK1/RIPK3/MLKL pathway. This represents the first report on the induction of the Z-DNA-mediated necroptosis by CBL0137 in the liver cancer cells, which should provide new perspectives for CBL0137 treatment of liver cancer.

Ceramides during Pregnancy and Obstetrical Adverse Outcomes

Ceramides are a group of sphingolipids located in the external plasma membrane layer and act as messengers in cellular pathways such as inflammatory processes and apoptosis. Plasma ceramides are biomarkers of cardiovascular disease, type 2 diabetes mellitus, Alzheimer's disease, various autoimmune conditions and cancer. During pregnancy, ceramides play an important role as stress mediators, especially during implantation, delivery and lactation. Based on the current literature, plasma ceramides could be potential biomarkers of obstetrical adverse outcomes, although their role in metabolic pathways under such conditions remains unclear. This review aims to present current studies that examine the role of ceramides during pregnancy and obstetrical adverse outcomes, such as pre-eclampsia, gestational diabetes mellitus and other complications.

MLKL regulates Cx43 ubiquitinational degradation and mediates neuronal necroptosis in ipsilateral thalamus after focal cortical infarction

Necroptosis is known to play an important role in the pathophysiology of cerebral ischemia; however, its role in the occurrence of secondary thalamic injury after focal cerebral infarction and the mechanism about how mixed lineage kinase domain-like (MLKL) executes necroptosis in this pathophysiology are still unclear. In this study, Sprague-Dawley rats were subjected to distal branch of middle cerebral artery occlusion (dMCAO). The expression of MLKL, connexin 43 (Cx43) and Von Hippel-Lindau (VHL) in vitro and in vivo were assessed by Western blot. Bioinformatic methods were used to predict the potential binding sites where MLKL interacted with Cx43, and the ubiquitination degradation of Cx43 regulated by VHL. The interactions among MLKL, Cx43, VHL, and Ubiquitin were assessed by immunoprecipitation. Dye uptake assay were used to examine the Cx43 hemichannels. Intracellular Ca2+ concentration was measured using Fluo-4 AM. Overexpression and site-directed mutagenesis studies were used to study the mechanisms by which MLKL regulates Cx43 ubiquitinational degradation to mediate neuronal necroptosis. We found that MLKL and Cx43 were upregulated in the ventral posterolateral nucleus (VPN) of the ipsilateral thalamus after dMCAO. In the in vitro experiments MLKL and Cx43 were upregulated after TSZ-mediated necroptosis in SH-SY5Y cells. The interaction between MLKL and Cx43 inhibited the K48-linked ubiquitination of Cx43 in necroptotic SH-SY5Y cells. VHL is an E3 ubiquitin ligase for Cx43, and MLKL competes with VHL for binding to Cx43. Interaction of MLKL Ser454 with Cx43 can trigger the opening of Cx43 hemichannels, causing increased intracellular Ca2+, and cell necroptosis. This innovative study at animal models, cellular, and molecular levels is anticipated to clarify the roles of MLKL and Cx43 in thalamic damage after focal cortical infarction. Our findings may help identify novel targets for neurological recovery after cortical infarction.

Role of necroptosis and immune infiltration in preeclampsia: novel insights from bioinformatics analyses

BACKGROUND

Preeclampsia (PE) is a serious pregnancy complication that can adversely affect the mother and fetus. Necroptosis is a recently discovered new form of programmed cell death involved in the pathological process of various pregnancy complications. Our study aimed to identify the necroptosis-related differentially expressed genes (NRDEGs), create a diagnosis model and related disease subtypes model based on these genes, and further investigate their relationship with immune infiltration.

METHODS

In this study, we identified NRDEGs by analyzing data from various databases, including Molecular Signatures, GeneCards, and Gene Expression Omnibus (GEO). Using minor absolute shrinkage and selection operator (LASSO) and logistic Cox regression analysis, we developed a novel PE diagnosis model based on NRDEGs. Furthermore, we developed PE subtype models using consensus clustering analysis based on key gene modules screened out by weighted correlation network analysis (WGCNA). Finally, we identified the difference in immune infiltration between the PE and control groups as well as between both PE subtypes by analyzing the immune cell infiltration across combined datasets and PE datasets.

RESULTS

Our study discovered that the necroptosis pathway was significantly enriched and active in PE samples. We identified nine NRDEGs that involved in this pathway, including BRAF, PAWR, USP22, SYNCRIP, KRT86, MERTK, BAP1, CXCL5, and STK38. Additionally, we developed a diagnostic model based on a regression model including six NRDEGs and identified two PE subtypes: Cluster1 and Cluster2, based on key module genes. Furthermore, correlation analysis showed that the abundance of immune cell infiltration was related to necroptosis genes and PE disease subtypes.

CONCLUSION

According to the present study, necroptosis is a phenomenon that occurs in PE and is connected to immune cell infiltration. This result suggests that necroptosis and immune-related factors may be the underlying mechanisms of PE pathophysiology. This study opens new avenues for future research into PE's pathogenesis and treatment options.

Necroptosis in the pathophysiology of preeclampsia

Necroptosis is a newly-identified form of gene-regulated cell necrosis that is increasingly considered to be a pathway associated with human pathophysiological conditions. Cells undergoing necroptosis exhibit necrotic phenotypes, including disruption of the plasma membrane integrity, organelle swelling, and cytolysis. Accumulating evidence suggests that trophoblast necroptosis plays a complex role in preeclampsia (PE). However, the exact pathogenesis remains unclear. Its unique mechanisms of action in various diseases are expected to provide prospects for the treatment of PE. Therefore, it is necessary to further explore its molecular mechanism in PE in order to identify potential therapeutic options. This review examines the current knowledge regarding the role and mechanisms of necroptosis in PE and provides a theoretical basis for new therapeutic targets for PE.

Healthy and diseased placental barrier on-a-chip models suitable for standardized studies

Pathologies associated with uteroplacental hypoxia, such as preeclampsia are among the leading causes of maternal and perinatal morbidity in the world. Its fundamental mechanisms are yet poorly understood due to a lack of good experimental models. Here we report an in vitro model of the placental barrier, based on co-culture of trophoblasts and endothelial cells against a collagen extracellular matrix in a microfluidic platform. The model yields a functional syncytium with barrier properties, polarization, secretion of relevant extracellular membrane components, thinning of the materno-fetal space, hormone secretion, and transporter function. The model is exposed to low oxygen conditions and perfusion flow is modulated to induce a pathological environment. This results in reduced barrier function, hormone secretion, and microvilli as well as an increased nuclei count, characteristics of preeclamptic placentas. The model is implemented in a titer plate-based microfluidic platform fully amenable to high-throughput screening. We thus believe this model could aid mechanistic understanding of preeclampsia and other placental pathologies associated with hypoxia/ischemia, as well as support future development of effective therapies through target and compound screening campaigns. STATEMENT OF SIGNIFICANCE: : The human placenta is a unique organ sustaining fetus growth but is also the source of severe pathologies, such as Preeclampsia. Though leading cause of perinatal mortality in the world, preeclampsia remains untreatable due to a lack of relevant in vitro placenta models. To better understand the pathology, we have developed 3D placental barrier models in a microfluidic device. The platform allows parallel culture of 40 perfused physiological miniaturized placental barriers, comprising a differentiated syncytium and endothelium that have been validated for transporter functions. Exposure to a hypoxic and ischemic environment enabled the mimicking of preeclamptic characteristics in high-throughput, which we believe could lead to a better understanding of the pathology as well as support future effective therapies development.

Distinct Changes in Placental Ceramide Metabolism Characterize Type 1 and 2 Diabetic Pregnancies with Fetal Macrosomia or Preeclampsia

Disturbances of lipid metabolism are typical in diabetes. Our objective was to characterize and compare placental sphingolipid metabolism in type 1 (T1D) and 2 (T2D) diabetic pregnancies and in non-diabetic controls. Placental samples from T1D, T2D, and control pregnancies were processed for sphingolipid analysis using tandem mass spectrometry. Western blotting, enzyme activity, and immunofluorescence analyses were used to study sphingolipid regulatory enzymes. Placental ceramide levels were lower in T1D and T2D compared to controls, which was associated with an upregulation of the ceramide degrading enzyme acid ceramidase (ASAH1). Increased placental ceramide content was found in T1D complicated by preeclampsia. Similarly, elevated ceramides were observed in T1D and T2D pregnancies with poor glycemic control. The protein levels and activity of sphingosine kinases (SPHK) that produce sphingoid-1-phosphates (S1P) were highest in T2D. Furthermore, SPHK levels were upregulated in T1D and T2D pregnancies with fetal macrosomia. In vitro experiments using trophoblastic JEG3 cells demonstrated increased SPHK expression and activity following glucose and insulin treatments. Specific changes in the placental sphingolipidome characterize T1D and T2D placentae depending on the type of diabetes and feto-maternal complications. Increased exposure to insulin and glucose is a plausible contributor to the upregulation of the SPHK-S1P-axis in diabetic placentae.

Inhibition of Ceramide Synthesis Attenuates Chronic Ethanol Induced Cardiotoxicity by Restoring Lysosomal Function and Reducing Necroptosis

AIMS

Chronic alcohol misuse could cause alcoholic cardiomyopathy (ACM), and the specific mechanisms remained largely unknown. In this study, we aimed to explore the effects of endogenous ceramides on chronic ethanol-induced myocardial injury or cell loss (e.g. necroptosis).

METHODS

We established chronic alcohol intoxication models in vivo (male C57BL/6 mice) and in vitro (H9c2 cardiomyoblasts). The ceramide profiles were analyzed in mice myocardium and cultured cardiomyocytes. Further research on the role of ceramides and underlying signaling pathways was carried out in H9c2 cells.

RESULTS AND CONCLUSIONS

The ceramide profiles analysis revealed increased long and very long-chain ceramides in alcoholic myocardium and ethanol-treated cardiomyocytes. Next, we proved that endogenous ceramide inhibition could reduce necroptosis and alleviate cardiomyocytes injury as suggested by decreased levels of p-RIPK1, p-RIPK3 and p-MLKL proteins and cardiac injury factors expression. Furthermore, we found that lysosomal dysfunction also contributed to alcohol-induced cardiac damage and inhibiting ceramide biosynthesis could repaired this to some extent. Cells studies with exogenous C6 ceramide confirmed the pleotropic roles of ceramide in myocardial damage by causing both necroptosis and lysosomal dysfunction. Finally, our data suggested that lysosomal dysfunction could sensitize cardiomyocytes to induction of necroptosis due to the restriction on degradation of RIPK1/RIPK3 proteins. In conclusion, chronic ethanol treatment boosted myocardial ceramide synthesis in animal hearts and cultured cardiomyocytes. Moreover, ceramides exerted crucial roles in the intrinsic signaling pathways of alcohol-induced cardiotoxicity. Targeting ceramide biosynthesis to simultaneously attenuate necroptosis and lysosomal dysfunction might be a novel strategy for preventing alcoholic cardiotoxicity.

TMBIM4 Deficiency Facilitates NLRP3 Inflammasome Activation-Induced Pyroptosis of Trophoblasts: A Potential Pathogenesis of Preeclampsia

Impaired invasion of EVTs results in inadequate remodelling of arteries and poor placentation, leading to PE. TMBIM4 was found to promote the migration and invasion of human osteosarcoma U2-OS and breast cancer MCF7 cell lines. However, the effect of TMBIM4 on trophoblast biological behaviour and its relevance to PE pathophysiology remain unclear. In this study, we confirmed that TMBIM4 was highly expressed in cytotrophoblasts, syncytiotrophoblasts, and EVTs of the human placenta during early pregnancy. By comparing the expression levels of TMBIM4 in the placenta of women with normal-term pregnancy and PE, TMBIM4 was found to be significantly decreased in PE. Thereafter, we determined the expression of TMBIM4 in the LPS-treated first-trimester human trophoblast cell line HTR-8/SVneo (mimicking a PE-like cell model), and determined the effect of TMBIM4 on trophoblast function and its underlying mechanism. LPS treatment reduced the expression of TMBIM4 and induced NLRP3 inflammasome activity in HTR-8/SVneo cells. KO of TMBIM4 in the HTR-8/SVneo cell line impaired cell viability, migration, and invasion, which was more severe in the LPS/ATP-treated TMBIM4-KO cell line. Moreover, TMBIM4 deficiency enhanced NLRP3 inflammasome activity and promoted subsequent pyroptosis, with or without LPS/ATP treatment. The negative relationship between TMBIM4 expression and NLRP3 inflammatory activity was verified in PE placentas. Inhibiting the NLRP3 inflammasome with MCC950 in HTR-8/SVneo cells alleviated LPS/ATP-induced pyroptosis and damaged cell function in the TMBIM4-KO cell line. Overall, this study revealed a new PE-associated protein, TMBIM4, and its biological significance in trophoblast pyroptosis mediated by the NLRP3 inflammasome. TMBIM4 may serve as a potential target for the treatment of placental inflammation-associated PE.

Omics approaches to better understand the molecular mechanism of necroptosis and their translational implications

Necroptosis is a type of programed cell death characterized by an inflammatory phenotype due to extensive membrane permeabilization and rupture. Initiation of necroptosis involves activation of tumor necrosis factor receptors by tumor necrosis factor alpha (TNFα) followed by coordinated activities of receptor-interacting protein kinases and mixed lineage kinase-like protein (MLKL). Subsequently, MLKL undergoes phosphorylation and translocates to the plasma membrane, leading to permeabilization. Such permeabilization results in the release of various cytokines and causes extensive inflammatory activity at the organismal level. This inflammatory activity is one of the major differences between apoptosis and necroptosis and links necroptosis to several human pathologies that exhibit inflammation, in addition to the ultimate cell death phenotype. Given the crosstalk between the activation of cell death pathway and inflammatory activity, approaches that provide insights on the regulation of transcripts, proteins and their processing at the global level have substantially improved our understanding of necroptosis and its involvement in different disease states. In this review, we highlight recent omic studies probing the transcriptome, proteome and lipidome which elucidate potential new mechanisms and signaling pathways during necroptosis and the necroptosis-associated inflammatory activity observed in various diseases. We specifically focus on studies investigating the transcriptome and intracellular and released proteome that contribute to inflammatory nature of necroptotic cells. We also highlight different lipids that have been implicated in necroptosis and lipidomic studies identifying lipid players in necroptosis. Finally, we review studies which suggest certain necroptosis-related genes as potential prognosis markers for different cancers and discuss their translational implications.

RIPK1 and RIPK3 are positive prognosticators for cervical cancer patients and C2 ceramide can inhibit tumor cell proliferation in vitro

Introduction

The enzymes Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) und 3 (RIPK3) as well as the protein Mixed lineage kinase domain like pseudokinase (pMLKL) play a role in the signaling cascade of necroptosis. This is a form of programmed cell death which is caspase-independent. High-risk human papilloma virus infection can inhibit necroptosis. Thereby, a persistent infection and consequently the development of cervical cancer can be triggered. Aim of this study was the analysis of the expression of RIPK1, RIPK3 and pMLKL in cervical cancer tissue and the evaluation of its prognostic value on overall survival, progression-free survival and additional clinical parameters.

Methods

The expression of RIPK1, RIPK3, and pMLKL in cervical cancer tissue microarrays of n = 250 patients was analyzed immunohistochemically. Further, the effect of C2 ceramide on several cervical cancer cell lines (CaSki, HeLa, SiHa) was examined. C2 ceramide is a biologically active short-chain ceramide that induces necroptosis in human luteal granulosa cells.

Results

Significantly longer overall survival and progression-free survival rates could be detected in cervical cancer patients expressing nuclear RIPK1 or RIPK3 alone or simultaneously (RIPK1 and RIPK3). Cell viability and proliferation was reduced through C2 ceramide stimulation of cervical cancer cells. Simultaneous stimulation of C2 ceramide and the pan-caspase inhibitor Z-VAD-fmk, or the RIPK1-inhibitor necrostatin-1, partly reversed the negative effect of C2 ceramide on cell viability. This observation could imply that caspase-dependent and -independent forms of cell death, including necroptosis, can occur. AnnexinV-FITC apoptosis staining induced a significant increase in apoptotic cells in CaSki and SiHa cells. The stimulation of CaSki cells with C2 ceramide led to a significant percentual increase in necrotic/intermediate (dying) cells after stimulation with C2 ceramide. In addition, after stimulation with C2 ceramide, CaSki and HeLa cells live cell imaging showed morphological changes which are common for necroptosis.

Discussion

In conclusion, RIPK1 and RIPK3 are independent positive predictors for overall survival and progression-free survival in cervical cancer patients. C2 ceramide can reduce cell viability and proliferation in cervical cancer cells by inducing most likely both apoptosis and necroptosis.

Role of Ceramides and Lysosomes in Extracellular Vesicle Biogenesis, Cargo Sorting and Release

Cells have the ability to communicate with their immediate and distant neighbors through the release of extracellular vesicles (EVs). EVs facilitate intercellular signaling through the packaging of specific cargo in all type of cells, and perturbations of EV biogenesis, sorting, release and uptake is the basis of a number of disorders. In this review, we summarize recent advances of the complex roles of the sphingolipid ceramide and lysosomes in the journey of EV biogenesis to uptake.

Attenuation of placental pyruvate kinase M2 promotes oxidative imbalance and enhances inflammatory- apoptosis cross talk in rats with hyperhomocysteinemia associated pregnancy loss.. [DOI: 10.21203/rs.3.rs-1997950/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

10-15% of clinically recognized pregnancies end in miscarriage. Hyperhomocysteinemia in pregnant women has been associated with deep venous thrombosis, recurrent miscarriage, preeclampsia to name a few. Impaired placental function due to overt oxidative stress is one of the key mechanisms in development of pregnancy loss. Paucity of pathway–based microarray approach in embryonic–endometrial communication warrants elucidation of distinct profile of miRNAs in hyperhomocysteinemia-associated pregnancy loss (HAPL). Hyperhomocysteinemia was induced at a dose of 100mg/kg body-weight/day for D1-D18 of pregnancy. Placental histology by haematoxylin-eosin staining documented thrombus with reduced area of spongiotropoblasts in chorionic plate vessel. Placental mRNA was subjected to microarray analysis followed by pathway-analysis using Ingenuity Pathway Analysis (IPA). Genes involved in reproductive physiology, inflammatory pathways, immune responses, homocysteine metabolism, glucose metabolism, and oxidative stress were differentially expressed in HAPL. 21 pathways documented by IPA, were skewed to 10 by recursive feature elimination highlighting possible deregulation/s. Expression/s was re-confirmed by quantitative real- time PCR (qRT-PCR), western blot and flow cytometric analysis (FACS). Nine priori molecules (PKM2, AKT, PI3K, NF-κB, COX-2, sflt-1, HIF-1α, bax, caspase 9) were specifically modulated in HAPL as demonstrated by protein and mRNA expression. A parallel increase in insulin signaling (PI3K+,AKT+), inflammation (COX2+,NF-κB+), hypoxia (sflt-1+,HIF-1α+), apoptosis (bax+,caspase9+) with concomitant decrease in pyruvate kinase M2 in hyperhomocysteinemic placental cells by FACS with CD56, a marker for pregnancy loss was documented. The findings provide evidence that an oxidative stress-mediated placental damage perhaps represents the pathogenesis of HAPL, which may explore pathway-based therapeutic options for recurrent miscarriage.10–15% of clinically recognized pregnancies end in miscarriage. Hyperhomocysteinemia in pregnant women has been associated with deep venous thrombosis, recurrent miscarriage, preeclampsia to name a few. Impaired placental function due to overt oxidative stress is one of the key mechanisms in development of pregnancy loss. Paucity of pathway–based microarray approach in embryonic–endometrial communication warrants elucidation of distinct profile of miRNAs in hyperhomocysteinemia-associated pregnancy loss (HAPL). Hyperhomocysteinemia was induced at a dose of 100mg/kg body-weight/day for D1-D18 of pregnancy. Placental histology by haematoxylin-eosin staining documented thrombus with reduced area of spongiotropoblasts in chorionic plate vessel. Placental mRNA was subjected to microarray analysis followed by pathway-analysis using Ingenuity Pathway Analysis (IPA). Genes involved in reproductive physiology, inflammatory pathways, immune responses, homocysteine metabolism, glucose metabolism, and oxidative stress were differentially expressed in HAPL. 21 pathways documented by IPA, were skewed to 10 by recursive feature elimination highlighting possible deregulation/s. Expression/s was re-confirmed by quantitative real- time PCR (qRT-PCR), western blot and flow cytometric analysis (FACS). Nine priori molecules (PKM2, AKT, PI3K, NF-κB, COX-2, sflt-1, HIF-1α, bax, caspase 9) were specifically modulated in HAPL as demonstrated by protein and mRNA expression. A parallel increase in insulin signaling (PI3K+,AKT+), inflammation (COX2+,NF-κB+), hypoxia (sflt-1+,HIF-1α+), apoptosis (bax+,caspase9+) with concomitant decrease in pyruvate kinase M2 in hyperhomocysteinemic placental cells by FACS with CD56, a marker for pregnancy loss was documented. The findings provide evidence that an oxidative stress-mediated placental damage perhaps represents the pathogenesis of HAPL, which may explore pathway-based therapeutic options for recurrent miscarriage.

Dissecting the Roles of Lipids in Preeclampsia

Preeclampsia is a multisystem pregnancy disorder that is characterized by different degrees of placental malperfusion, with release of antiangiogenic factors into the circulation, leading to maternal vascular endothelial injury and high blood pressure. As a major cause of maternal and perinatal mortality and morbidity worldwide, once preeclampsia has been diagnosed, there are no curative treatments except for delivery. Lipids serve as ubiquitous and multifunctional metabolites that are integral and essential to many diverse functions on both a cellular and organismal level. Lipid metabolic abnormalities have emerged as potential risk factors for the development and progression of preeclampsia. This review comprehensively examines decades of discovery to illuminate the roles of lipids and dysregulation in the levels of various lipid classes in preeclampsia. In addition, the roles of lipids are summarized to further understand the pathogenic mechanisms of preeclampsia. Overall, the review highlights the promising potential of pathophysiology and lipid-targeting therapeutic strategies in preeclampsia.

Ferroptosis-Related Proteins Are Potential Diagnostic Molecular Markers for Patients with Preeclampsia

Preeclampsia (PE) is the leading cause of maternal and fetal mortality and morbidity. Early and accurate diagnosis is critical to reduce mortality. Placental oxidative stress has been identified as a major pathway to the development of PE. Ferroptosis, a new form of regulated cell death, is associated with iron metabolism and oxidative stress, and has been suspected to play a role in the pathophysiology of PE, although the mechanism is yet to be elucidated. The identification of potential ferroptosis-related biomarkers is of great significance for the early diagnosis and treatment of PE. A gene expression dataset of peripheral blood samples was downloaded from the Gene Expression Omnibus (GEO) dataset. Differentially expressed genes (DEGs) were filtrated with the R package “limma”. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the DEGs were then conducted. Ferroptosis-related DEGs were screened by overlapping the ferroptosis-related genes with DEGs. The protein−protein interaction (PPI) network was used to identify the key ferroptosis-related DEGs. Enzyme-linked immunosorbent assay (ELISA) was used to validate changes in the selected key ferroptosis-related DEGs. The correlations between the key genes and clinical and pathological characteristics were analyzed. Finally, the diagnostic value of these key genes for PE was confirmed by a receiver operating characteristic (ROC) curve. A total of 5913 DEGs were identified and 45 ferroptosis-related DEGs were obtained. Besides, ferroptosis-related pathways were enriched by KEGG using DEGs. The PPI network showed that p53 and c-Jun were the critical hub genes. ELISA showed that p53 in the serum of PE patients was higher than that of the control group, while c-Jun was lower than that of the control group. Analysis of the clinicopathological features showed that p53 and c-Jun were correlated with the PE characteristics. Finally, based on the area under curve (AUC) values, c-Jun had the superior diagnostic power (AUC = 0.87, p < 0.001), followed by p53 (AUC = 0.75, p < 0.001). Our study identified that two key genes, p53 and c-Jun, might be potential diagnostic biomarkers of PE.

Phosphoglycerate mutase 5 promotes necroptosis in trophoblast cells through activation of dynamin-related protein 1 in early-onset preeclampsia

OBJECTIVES

Placentae from patients with preeclampsia have increased susceptibility to necroptosis and phosphoglycerate mutase 5 (PGAM5) plays a role in many necrosis pathways. We determined whether PGAM5 promotes necroptosis of trophoblast cells and the underlying mechanisms in this study.

METHODS

The injury model was established by treating JEG3 cells with hypoxia for 24 h. The functional measurements were assessed by the cell counting kit-8, propidium iodide (PI)/Annexin V staining, JC-1 staining and firefly luciferase ATP assay. The expression of proteins in human placentae and JEG3 cells was measured Western blot. PGAM5 was knocked down to study its role in hypoxia-induced necroptosis.

RESULTS

The placentae from patients with preeclampsia showed up-regulation of PGAM5 and decreased levels of p-Drp1-S637, accompanied by increased necroptosis-relevant proteins expression. The expression of PGAM5 in JEG3 cells was up-regulated under hypoxia, which promoted dephosphorylation of Drp1 at Serine 637 residue, mitochondrial dysfunction (elevated ROS level and reduced mitochondrial membrane potential and ATP content) and cellular necroptosis (increased PI⁺ /Annexin V⁺ cells and decreased cell viability), accompanied by increased expression of necroptosis-relevant proteins; knockdown of PGAM5 attenuated these phenomena.

CONCLUSIONS

Our results indicate that PGAM5 can promote necroptosis in trophoblast cells through, at least in part, activation of Drp1. It may be used as a new therapeutic target to prevent trophoblast dysfunction in preeclampsia.

The Targeting of Nuclear Factor Kappa B by Drugs Adopted for the Prevention and Treatment of Preeclampsia

Preeclampsia (PE) is characterised by high levels and activity of the transcription factor Nuclear Factor kappa B (NFĸB) in the maternal blood and placental cells. This factor is responsible for the regulation of over 400 genes known to influence processes related to inflammation, apoptosis and angiogenesis, and cellular responses to oxidative stress and hypoxia. Although high NFĸB activity induces hypoxia and inflammation, which are beneficial for the process of implantation, NFĸB level should be reduced in the later stages of physiological pregnancy to favour maternal immunosuppression and maintain gestation. It is believed that the downregulation of NFĸB activity by pharmacotherapy might be a promising way to treat preeclampsia. Interestingly, many of the drugs adopted for the prevention and treatment of preeclampsia have been found to regulate NFĸB activity. Despite this, further innovation is urgently needed to ensure treatment safety and efficacy. The present article summarizes the current state of knowledge about the drugs recommended by cardiology, obstetrics, and gynaecology societies for the prevention and treatment of preeclampsia with regard to their impact on the cellular regulation of NFĸB pathways.

Cryptotanshinone Induces Necroptosis through Ca2+ Release and ROS Production in vitro and in vivo

BACKGROUND

Necroptosis is a type of programmed necrosis mediated by receptor-interacting protein kinases 1 and 3 (RIP1 and RIP3), which is morphologically characterized by enlarged organelles, ruptured plasma membrane, and subsequent loss of intracellular contents. Cryptotanshinone (CPT), a diterpene quinone compound extracted from the root of Salvia miltiorrhiza Bunge, has been reported to have significant anticancer activities. However, the detailed mechanism of CPT has not been clearly illustrated.

OBJECTIVE

The present study aimed to explore the cell death type and mechanisms of CPT-induced in non-small cell lung cancer (NSCLC) cells.

METHODS

The cytotoxicity of CPT on A549 cells was assessed by MTS assay. Ca2+ release and reactive oxygen species (ROS) generation were detected by flow cytometry. The changes in mitochondrial membrane potential (MMP) were observed through JC-1 staining. The expressions of p-RIP1, p-RIP3, p-MLKL, and MAPKs pathway proteins were analyzed by western blotting analysis. The efficacy of CPT in vivo was evaluated by the Lewis lung carcinoma (LLC) xenograft mice model. Blood samples were collected for hematology analysis. ELISA investigated the effects of CPT on tumor necrosis factor α (TNF-α). Hematoxylin and eosin staining (HE) was used to determine the tumor tissues. Proteins' expression of tumor tissues was quantified by western blotting.

RESULTS

CPT inhibited the cell viability of A549 cells in a time- and concentration-dependent manner, which was reversed by Necrostatin-1 (Nec-1). In addition, CPT treatment increased the expression of p-RIP1, p-RIP3, p-MLKL, the release of Ca2+, ROS generation, and the MAPKs pathway activated in A549 cells. Moreover, animal experiment results showed that intraperitoneal injection of CPT (15 mg/kg and 30 mg/kg) significantly inhibited tumor growth in C57BL/6 mice without affecting the bodyweight and injuring the organs.

CONCLUSION

Our findings suggested that CPT-induced necroptosis via RIP1/RIP3/MLKL signaling pathway both in vitro and in vivo, indicating that CPT may be a promising agent in the treatment of NSCLC.

Role of GRK2 in Trophoblast Necroptosis and Spiral Artery Remodeling: Implications for Preeclampsia Pathogenesis

Impaired invasion of extravillous trophoblasts and severe oxidative stress manifest the poor placentation in preeclampsia, which is life-threatening and more than a hypertensive disease of pregnancy. Previous studies have reported that G protein-coupled receptor kinases (GRKs) play a key role in initiating hypertension and hypertensive renal damage, yet little evidence so far suggests a link between GRKs and preeclampsia-related hypertension. Here, we demonstrate GRK2 expression is significantly downregulated (P < 0.0001) in preeclamptic placentae compared to normotensive controls. Knockdown or inhibition of GRK2 in placentae caused insufficient arterial remodeling and elevated trophoblast necroptosis in vivo. These further induced preeclampsia-like phenotype in mice: hypertension, proteinuria, and elevated pro-angiogenic cytokines. By human extra-villous invasive trophoblast cell line (HTR8/SVneo cells), we revealed the knockdown or inhibition of GRK2 triggered excessive death with typical necroptotic characteristics: nuclear envelope rupture and the activation of RIPK1, RIPK3, and MLKL. Necrostatin-1, an inhibitor of RIPK1, is able to restore the survival of trophoblasts. Together, our findings demonstrated that insufficient GRK2 activity compromises spiral artery remodeling and initiates necrotic events in placentae, thereby leading to preeclampsia. These findings advance our understanding of GRK2 in the pathogenesis of preeclampsia and could shed light on a potential treatment for preeclampsia.

Early-pregnancy prediction of risk for pre-eclampsia using maternal blood leptin/ceramide ratio: discovery and confirmation

OBJECTIVE

This study aimed to develop a blood test for the prediction of pre-eclampsia (PE) early in gestation. We hypothesised that the longitudinal measurements of circulating adipokines and sphingolipids in maternal serum over the course of pregnancy could identify novel prognostic biomarkers that are predictive of impending event of PE early in gestation.

STUDY DESIGN

Retrospective discovery and longitudinal confirmation.

SETTING

Maternity units from two US hospitals.

PARTICIPANTS

Six previously published studies of placental tissue (78 PE and 95 non-PE) were compiled for genomic discovery, maternal sera from 15 women (7 non-PE and 8 PE) enrolled at ProMedDx were used for sphingolipidomic discovery, and maternal sera from 40 women (20 non-PE and 20 PE) enrolled at Stanford University were used for longitudinal observation.

OUTCOME MEASURES

Biomarker candidates from discovery were longitudinally confirmed and compared in parallel to the ratio of placental growth factor (PlGF) and soluble fms-like tyrosine kinase (sFlt-1) using the same cohort. The datasets were generated by enzyme-linked immunosorbent and liquid chromatography-tandem mass spectrometric assays.

RESULTS

Our discovery integrating genomic and sphingolipidomic analysis identified leptin (Lep) and ceramide (Cer) (d18:1/25:0) as novel biomarkers for early gestational assessment of PE. Our longitudinal observation revealed a marked elevation of Lep/Cer (d18:1/25:0) ratio in maternal serum at a median of 23 weeks' gestation among women with impending PE as compared with women with uncomplicated pregnancy. The Lep/Cer (d18:1/25:0) ratio significantly outperformed the established sFlt-1/PlGF ratio in predicting impending event of PE with superior sensitivity (85% vs 20%) and area under curve (0.92 vs 0.52) from 5 to 25 weeks of gestation.

CONCLUSIONS

Our study demonstrated the longitudinal measurement of maternal Lep/Cer (d18:1/25:0) ratio allows the non-invasive assessment of PE to identify pregnancy at high risk in early gestation, outperforming the established sFlt-1/PlGF ratio test.

Preeclampsia: From Cellular Wellness to Inappropriate Cell Death, and the Roles of Nutrition

Preeclampsia is one of the most common obstetrical complications worldwide. The pathomechanism of this disease begins with abnormal placentation in early pregnancy, which is associated with inappropriate decidualization, vasculogenesis, angiogenesis, and spiral artery remodeling, leading to endothelial dysfunction. In these processes, appropriate cellular deaths have been proposed to play a pivotal role, including apoptosis and autophagy. The proper functioning of these physiological cell deaths for placentation depends on the wellbeing of the trophoblasts, affected by the structural and functional integrity of each cellular component including the cell membrane, mitochondria, endoplasmic reticulum, genetics, and epigenetics. This cellular wellness, which includes optimal cellular integrity and function, is heavily influenced by nutritional adequacy. In contrast, nutritional deficiencies may result in the alteration of plasma membrane, mitochondrial dysfunction, endoplasmic reticulum stress, and changes in gene expression, DNA methylation, and miRNA expression, as well as weakened defense against environmental contaminants, hence inducing a series of inappropriate cellular deaths such as abnormal apoptosis and necrosis, and autophagy dysfunction and resulting in abnormal trophoblast invasion. Despite their inherent connection, the currently available studies examined the functions of each organelle, the cellular death mechanisms and the nutrition involved, both physiologically in the placenta and in preeclampsia, separately. Therefore, this review aims to comprehensively discuss the relationship between each organelle in maintaining the physiological cell death mechanisms and the nutrition involved, and the interconnection between the disruptions in the cellular organelles and inappropriate cell death mechanisms, resulting in poor trophoblast invasion and differentiation, as seen in preeclampsia.

Profiling of sphingolipids in Caenorhabditis elegans by two-dimensional multiple heart-cut liquid chromatography - mass spectrometry

Sphingolipids exert important functions in cells, ranging from stabilising the cell membrane to bioactive signalling in signal transduction pathways. Changed concentrations of sphingolipids are associated with, among others, neurodegenerative and cardiovascular diseases. In this work, we present a novel two-dimensional liquid chromatography method (2D-LC) coupled to tandem mass spectrometry (MS/MS) for the identification of ceramides, hexosylceramides and sphingomyelins in the model organism Caenorhabditis elegans (C. elegans). The method utilises a multiple heart-cut approach with a hydrophilic interaction liquid chromatography (HILIC) separation in the first dimension. The fractions of the sphingolipid classes were cut out and thereby separated from the abundant glycerolipids, which offers a simplified sample preparation and a high degree of automation as it compensates the alkaline depletion step usually conducted prior to the chromatographic analysis. The fractions were stored in a sample loop and transferred onto the second column with the combination of two six port valves. A reversed phase liquid chromatography was performed as the second dimension and allowed for a separation of the species within a sphingolipid class and according to the fatty acid moiety of the sphingolipid. The segregation of the abundant glycerolipids and the reduced matrix effects allowed for better identification of low abundant species, especially dihydro-sphingolipids with a saturated sphingoid base. In addition, the separation of the three fractions was carried out parallel to the separation and equilibration in the first dimension, which leads to no extension of the analysis time for the 2D-LC compared to the one-dimensional HILIC method. In total 45 sphingolipids were detected in the C. elegans lipid extract and identified via accurate mass and MS/MS fragments.

miR-146a-5p-mediated suppression on trophoblast cell progression and epithelial-mesenchymal transition in preeclampsia

Objective

This study aims to identify the effect of miR-146a-5p on trophoblast cell invasion as well as the mechanism in preeclampsia (PE).

Methods

Expression levels of miR-146a-5p and Wnt2 in preeclamptic and normal placentae were quantified. Trophoblast cells (HTR-8) were separately transfected with miR-146a-5p mimic, miR-146a-5p inhibitor, pcDNA3.1-Wnt2 or sh-Wnt2, and then the expression levels of miR-146a-5p, Wnt2, and epithelial-mesenchymal transition (EMT)-related proteins (Vimentin, N-cadherin and E-cadherin) were measured. Moreover, the proliferative, migratory and invasive capacities of trophoblast cells were detected, respectively. Dual luciferase reporter assay determined the binding of miR-146a-5p and Wnt2.

Results

Compared with normal placental tissues, the placentae from PE patients showed higher miR-146a-5p expression and lower Wnt2 expression. Transfection of miR-146a-5p inhibitor or pcDNA3.1-Wnt2 exerted pro-migratory and pro-invasive effects on HTR-8 cells and encouraged EMT in HTR-8 cells; transfection with miR-146a-5p mimic or sh-Wnt2 weakened the proliferative, migratory and invasive capacities as well as reduced EMT process of HTR-8 cells. Moreover, Wnt2 overexpression could partially counteract the suppressive effects of miR-146a-5p overexpression on the progression and EMT of HTR-8 cells.

Conclusion

miR-146a-5p mediates trophoblast cell proliferation and invasion through regulating Wnt2 expression.

Efficacy of Low Molecular Heparin on Preeclampsia by Inhibiting Apoptosis of Trophoblasts via the p38MAPK Signaling Pathway

OBJECTIVE

To explore the efficacy of low molecular heparin on preeclampsia by inhibiting apoptosis of trophoblasts via the p38MAPK signaling pathway.

METHODS

A preeclampsia rat model was established, and the effects of low molecular heparin on preeclampsia via the p38MAPK signaling pathway were analyzed based on intervention of the rats with different combinations of low molecular heparin and p38MAPK signaling pathway activator. Furthermore, a hypoxia/reoxygenation model of trophoblasts in vitro was established to explore the effects of low molecular heparin on trophoblasts via the p38MAPK signaling pathway.

RESULTS

After treatment with low molecular heparin, pregnant rats in the heparin group showed significantly decreased blood pressure, 24 h proteinuria, and p38MAPK protein levels in placenta tissues and decreased apoptosis rate of placenta tissue cells (all P < 0.05) and showed more fetal rats and lowered weight of them (both P < 0.05) but showed no significant change in the weight of placenta (all P > 0.05). Pregnant rats treated with low molecular heparin and p38MAPK activator showed significantly higher blood pressure, 24 h proteinuria, and p38MAPK protein levels in placenta tissues and apoptosis rate of placenta tissue cells than those of pregnant rats in the heparin group (all P < 0.05) and also showed less fetal rats and lighter fetal rats than those in the heparin group (both P < 0.05) but showed no difference with them in the weight of placenta (P > 0.05). Further analysis revealed that low molecular heparin could protect the survival and migration of trophoblasts under hypoxia/reoxygenation conditions and reduce apoptosis of them (all P < 0.05).

CONCLUSION

Low molecular heparin can alleviate preeclampsia by inhibiting the p38MAPK signaling pathway and can inhibit apoptosis of trophoblasts and promote proliferation and migration of them.

Syncytiotrophoblast stress in early onset preeclampsia: The issues perpetuating the syndrome

Preeclampsia is a pregnancy-specific syndrome characterized by a sudden increase in blood pressure accompanied by proteinuria and/or maternal multi-system damage associated to poor fetal outcome. In early-onset preeclampsia, utero-placental perfusion is altered, causing constant and progressive damage to the syncytiotrophoblast, generating syncytiotrophoblast stress. The latter leads to the detachment and release of syncytiotrophoblast fragments, anti-angiogenic factors and pro-inflammatory molecules into maternal circulation, resulting in the emergence and persistence of the characteristic symptoms of this syndrome during pregnancy. Therefore, understanding the origin and consequences of syncytiotrophoblast stress in preeclampsia is vital to develop new therapeutic alternatives, focused on reducing the burden of this syndrome. In this review, we describe five central characteristics of syncytial stress that should be targeted or prevented in order to reduce preeclampsia symptoms: histological alterations, syncytiotrophoblast damage, antiangiogenic protein export, placental deportation, and altered syncytiotrophoblast turnover. Therapeutic management of these characteristics may improve maternal and fetal outcomes.

Physiological and pathological functions of sphingolipids in pregnancy

Signaling by the bioactive sphingolipid, sphingosine 1-phosphate (S1P), and its precursors are emerging areas in pregnancy research. S1P and ceramide levels increase towards end of gestation, suggesting a physiological role in parturition. However, high levels of circulating S1P and ceramide are correlated with pregnancy disorders such as preeclampsia, gestational diabetes mellitus and intrauterine growth restriction. Expression of placental and decidual enzymes that metabolize S1P and S1P receptors are also dysregulated during pregnancy complications. In this review, we provide an in-depth examination of the signaling mechanism of S1P and ceramide in various reproductive tissues during gestation. These factors determine implantation and early pregnancy success by modulating corpus luteum function from progesterone production to luteolysis through to apoptosis. We also highlight the role of S1P through receptor signaling in inducing decidualization and angiogenesis in the decidua, as well as regulating extravillous trophoblast migration to anchor the placenta into the uterine wall. Recent advances on the role of the S1P:ceramide rheostat in controlling the fate of villous trophoblasts and the role of S1P as a negative regulator of trophoblast syncytialization to a multinucleated placental barrier are discussed. This review also explores the role of S1P in anti-inflammatory and pro-inflammatory signaling, its role as a vasoconstrictor, and the effects of S1P metabolizing enzymes and receptors in pregnancy.

Ceramide-Induced Lysosomal Biogenesis and Exocytosis in Early-Onset Preeclampsia Promotes Exosomal Release of SMPD1 Causing Endothelial Dysfunction

Aberrant ceramide build-up in preeclampsia, a serious disorder of pregnancy, causes exuberant autophagy-mediated trophoblast cell death. The significance of ceramide accumulation for lysosomal biogenesis in preeclampsia is unknown. Here we report that lysosome formation is markedly increased in trophoblast cells of early-onset preeclamptic placentae, in particular in syncytiotrophoblasts. This is accompanied by augmented levels of transcription factor EB (TFEB). In vitro and in vivo experiments demonstrate that ceramide increases TFEB expression and nuclear translocation and induces lysosomal formation and exocytosis. Further, we show that TFEB directly regulates the expression of lysosomal sphingomyelin phosphodiesterase (L-SMPD1) that degrades sphingomyelin to ceramide. In early-onset preeclampsia, ceramide-induced lysosomal exocytosis carries L-SMPD1 to the apical membrane of the syncytial epithelium, resulting in ceramide accumulation in lipid rafts and release of active L-SMPD1 via ceramide-enriched exosomes into the maternal circulation. The SMPD1-containing exosomes promote endothelial activation and impair endothelial tubule formation in vitro. Both exosome-induced processes are attenuated by SMPD1 inhibitors. These findings suggest that ceramide-induced lysosomal biogenesis and exocytosis in preeclamptic placentae contributes to maternal endothelial dysfunction, characteristic of this pathology.

Sphingolipids in HDL - Potential markers for adaptation to pregnancy?

Plasma high density lipoprotein (HDL) exhibits many functions that render it an effective endothelial protective agent and may underlie its potential role in protecting the maternal vascular endothelium during pregnancy. In non-pregnant individuals, the HDL lipidome is altered in metabolic disease compared to healthy individuals and is linked to reduced cholesterol efflux, an effect that can be reversed by lifestyle management. Specific sphingolipids such as sphingosine-1-phosphate (S1P) have been shown to mediate the vaso-dilatory effects of plasma HDL via interaction with the endothelial nitric oxide synthase pathway. This review describes the relationship between plasma HDL and vascular function during healthy pregnancy and details how this is lost in pre-eclampsia, a disorder of pregnancy associated with widespread endothelial dysfunction. Evidence of a role for HDL sphingolipids, in particular S1P and ceramide, in cardiovascular disease and in healthy pregnancy and pre-eclampsia is discussed. Available data suggest that HDL-S1P and HDL-ceramide can mediate vascular protection in healthy pregnancy but not in preeclampsia. HDL sphingolipids thus are of potential importance in the healthy maternal adaptation to pregnancy.

Sphingolipids and Kidney Disease: Possible Role of Preeclampsia and Intrauterine Growth Restriction (IUGR)

Sphingolipids are now considered not only as constitutional components of the cellular membrane but also as essential bioactive factors regulating development and physiologic functions. Ceramide is a vital intermediate of sphingolipid metabolism, synthesized by de novo and salvage pathways, producing multiple types of sphingolipids and their metabolites. Although mutations in gene-encoding enzymes regulating sphingolipid synthesis and metabolism cause distinct diseases, an abnormal sphingolipid metabolism contributes to various pathologic conditions, including kidney diseases. Excessive accumulation of glycosphingolipids and promotion of the ceramide salvage and sphingosine-1-phosphate (S1P) pathways are found in the damaged kidney. Acceleration of the sphingosine kinase/S1P/S1P receptor (SphK/S1P/S1PR) axis plays a central role in deteriorating kidney functions. The SphK/S1P/S1PR signaling impairment is also found during pregnancy complications, such as preeclampsia and intrauterine growth restriction (IUGR). This mini-review discusses the current state of knowledge regarding the role of sphingolipid metabolism on kidney diseases, and the possible involvement of preeclampsia and IUGR conditions.

Targeting necroptosis in anticancer therapy: mechanisms and modulators

Necroptosis, a genetically programmed form of necrotic cell death, serves as an important pathway in human diseases. As a critical cell-killing mechanism, necroptosis is associated with cancer progression, metastasis, and immunosurveillance. Targeting necroptosis pathway by small molecule modulators is emerging as an effective approach in cancer therapy, which has the advantage to bypass the apoptosis-resistance and maintain antitumor immunity. Therefore, a better understanding of the mechanism of necroptosis and necroptosis modulators is necessary to develop novel strategies for cancer therapy. This review will summarize recent progress of the mechanisms and detecting methods of necroptosis. In particular, the relationship between necroptosis and cancer therapy and medicinal chemistry of necroptosis modulators will be focused on.

Early Pregnancy Vitamin D Binding Protein Is Independently Associated with the Development of Gestational Diabetes: A Retrospective Cohort Study

BACKGROUND

Vitamin D-binding protein (VDBP) has been implicated in several adverse pregnancy outcomes either directly or indirectly via influencing the concentrations of biologically active vitamin D metabolites. However, human studies exploring these metabolites in pregnancy remain sparse. Here, we examine whether VDBP and total, free, and bioavailable 25-hydroxyvitamin D (25(OH)D) metabolites in early pregnancy are associated with subsequent adverse pregnancy outcomes.

METHODS

We conducted a retrospective analysis of 304 pregnant women in early pregnancy (<20 weeks gestation). The demographic characteristics, anthropometric data, and total 25(OH)D were measured and plasma or serum samples were collected and bio-banked. Using these samples, we measured VDBP (polyclonal ELISA) and albumin (automated colorimetry), and calculated free and bioavailable 25(OH)D using validated formulae. Pregnancy outcomes were derived from scanned medical records. Regression models were used to analyse the relationships between vitamin D metabolites in early pregnancy and subsequent pregnancy outcomes (gestational diabetes mellitus (GDM), pre-eclampsia, preterm birth), with adjustment for predetermined clinically relevant maternal factors including age, body mass index (BMI), and ethnicity.

RESULTS

Lower VDBP concentrations were associated with higher glucose levels and a greater likelihood of developing GDM at 26-28 weeks gestation (odds ratio [OR] (95% CI) = 0.98 (0.97,0.99), p = 0.015). This finding remained significant after adjustment for maternal covariates including age, BMI, and ethnicity (β = -0.003, p = 0.03). Lower total, free and bioavailable 25(OH)D, but not VDBP, were associated with a shorter length of gestation, but only the relationship with total 25(OH)D remained significant after adjustment for the above maternal covariates (β = 0.02, p = 0.006).

CONCLUSIONS

This is the first study to examine VDBP, and total, free and bioavailable 25(OH)D in relation to pregnancy outcomes in a well characterised multi-ethnic cohort of pregnant women. Our findings show that VDBP and total 25(OH)D are associated with GDM and length of gestation, respectively; however, further investigations using large-scale prospective studies are needed to confirm our findings.

Differential expression of several factors involved in placental development in normal and abnormal condition

The placenta, a temporary organ that forms during pregnancy, is the largest fetal organ and the first to develop. It is recognized as an organ that plays a vital role as a metabolic and physical barrier in the fetoplacental unit; throughout fetal development it acts as the lungs, gut, kidneys, and liver of the fetus. When its two components, the fetal and the maternal one, successfully interact, pregnancy proceeds healthily. However, in some cases there may be pregnancy disorders, such as preeclampsia (PE) and gestational diabetes mellitus (GDM), which can lead to a different outcome for the mother and the newborn. In recent years, several studies have been conducted to try to understand how the expression of factors involved in the development of the placenta varies under pathological conditions compared with normal conditions. The purpose of this review is to summarize recent discoveries in this field.

On the role of sphingolipids in cell survival and death

Sphingolipids, universal components of biological membranes of all eukaryotic organisms, from yeasts to mammals, in addition of playing a structural role, also play an important part of signal transduction pathways. They participate or, also, ignite several fundamental subcellular signaling processes but, more in general, they directly contribute to key biological activities such as cell motility, growth, senescence, differentiation as well as cell fate, i.e., survival or death. The sphingolipid metabolic pathway displays an intricate network of reactions that result in the formation of multiple sphingolipids, including ceramide, and sphingosine-1-phosphate. Different sphingolipids, that have key roles in determining cell fate, can induce opposite effects: as a general rule, sphingosine-1-phosphate promotes cell survival and differentiation, whereas ceramide is known to induce apoptosis. Furthermore, together with cholesterol, sphingolipids also represent the basic lipid component of lipid rafts, cholesterol- and sphingolipid-enriched membrane microdomains directly involved in cell death and survival processes. In this review, we briefly describe the characteristics of sphingolipids and lipid membrane microdomains. In particular, we will consider the involvement of various sphingolipids per se and of lipid rafts in apoptotic pathway, both intrinsic and extrinsic, in nonapoptotic cell death, in autophagy, and in cell differentiation. In addition, their roles in the most common physiological and pathological contexts either as pathogenetic elements or as biomarkers of diseases will be considered. We would also hint how the manipulation of sphingolipid metabolism could represent a potential therapeutic target to be investigated and functionally validated especially for those diseases for which therapeutic options are limited or ineffective.

Regulation of Necroptosis by Phospholipids and Sphingolipids

Several non-apoptotic regulated cell death pathways have been recently reported. Necroptosis, a form of necrotic-regulated cell death, is characterized by the involvement of receptor-interacting protein kinases and/or the pore-forming mixed lineage kinase domain-like protein. Recent evidence suggests a key role for lipidic molecules in the regulation of necroptosis. The purpose of this mini-review is to outline the regulation of necroptosis by sphingolipids and phospholipids.

Increased placental mitochondrial fusion in gestational diabetes mellitus: an adaptive mechanism to optimize feto-placental metabolic homeostasis?

INTRODUCTION

Gestational diabetes mellitus (GDM), a common pregnancy disorder, increases the risk of fetal overgrowth and later metabolic morbidity in the offspring. The placenta likely mediates these sequelae, but the exact mechanisms remain elusive. Mitochondrial dynamics refers to the joining and division of these organelles, in attempts to maintain cellular homeostasis in stress conditions or alterations in oxygen and fuel availability. These remodeling processes are critical to optimize mitochondrial function, and their disturbances characterize diabetes and obesity.

METHODS AND RESULTS

Herein we show that placental mitochondrial dynamics are tilted toward fusion in GDM, as evidenced by transmission electron microscopy and changes in the expression of key mechanochemical enzymes such as OPA1 and active phosphorylated DRP1. In vitro experiments using choriocarcinoma JEG-3 cells demonstrated that increased exposure to insulin, which typifies GDM, promotes mitochondrial fusion. As placental ceramide induces mitochondrial fission in pre-eclampsia, we also examined ceramide content in GDM and control placentae and observed a reduction in placental ceramide enrichment in GDM, likely due to an insulin-dependent increase in ceramide-degrading ASAH1 expression.

CONCLUSIONS

Placental mitochondrial fusion is enhanced in GDM, possibly as a compensatory response to maternal and fetal metabolic derangements. Alterations in placental insulin exposure and sphingolipid metabolism are among potential contributing factors. Overall, our results suggest that GDM has profound impacts on placental mitochondrial dynamics and metabolism, with plausible implications for the short-term and long-term health of the offspring.

Plasma ceramide is increased and associated with proteinuria in women with pre-eclampsia and HELLP syndrome

OBJECTIVES

Ceramide is a sphingolipid with anti-angiogenic and pro-apoptotic properties that has shown to be increased in plasma of women with pre-eclampsia. We aimed to compare plasma and placental sphingolipid content among normotensive pregnant women and pre-eclamptic women with and without HELLP syndrome and we aimed to assess whether ceramide is related to hypertension and proteinuria in pre-eclampsia.

STUDY DESIGN

Case-control study. Participants were recruited from the Department of Obstetrics at the Academic Medical Center in Amsterdam, The Netherlands. In total 48 pregnant women were included: 24 with pre-eclampsia and 24 normotensive controls. Of the 24 pre-eclamptic women, 11 had HELLP syndrome.

MAIN OUTCOME MEASURES

Plasma and placental ceramide content and correlation with blood pressure and protein excretion in pre-eclampsia.

RESULTS

Total plasma, but not placental, ceramide was higher in pre-eclamptic women with HELLP syndrome (11200 95% CI 9531-12870 nmol/ml, n = 11) compared to pre-eclamptic women without HELLP (7413 95% CI 5928-8898 nmol/ml, n = 13, p < 0.001) and normotensive pregnant women (7404 95% CI 6695-8112 nmol/ml, n = 24, p < 0.001). Maternal circulating ceramide levels were strongly associated with proteinuria (r = 0.621, n = 24, p = 0.001) in pre-eclamptic women and inversely correlated with gestational age at delivery (r = 0.771, p < 0.01) in pre-eclamptic women with HELLP syndrome. Plasma ceramide was not correlated with blood pressure.

CONCLUSION

Plasma but not placental ceramide content is increased in women with pre-eclampsia and HELLP syndrome. The strong positive correlation with proteinuria and the inverse correlation with gestational age at delivery indicate that excess plasma ceramide may contribute to the pathophysiology of pre-eclampsia and HELLP.

Role of LAMA4 Gene in Regulating Extravillous Trophoblasts in Pathogenesis of Preeclampsia

Background

Preeclampsia is a severe obstetric complication affecting the health of pregnant women. The aim of this study was to determine the effect of LAMA4 gene on extravillous trophoblasts (EVTs) in the pathogenesis of preeclampsia and its possible regulatory mechanism.

Material/Methods

HTR-8/SVneo cells were transfected with small-interfering ribonucleic acid (siRNA) targeting LAMA. The LAMA4 protein level was detected via Western blotting. Moreover, the influences of LAMA4 gene on the proliferation, migration and invasion of HTR-8/SVneo cells were detected via cell counting kit-8 (CCK-8) assay and Transwell assay. We also assessed the influences of LAMA4 gene on vascular endothelial growth factor (VEGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) messenger RNA (mRNA) levels in HTR-8/SVneo cells as measured by reverse transcription-polymerase chain reaction (RT-PCR).

Results

The cell lines with downregulation of LAMA4 gene were successfully established by transfection. Compared with those in the normal group, the proliferation, migration, and invasion of HTR-8/SVneo cells declined, the VEGF mRNA level was reduced, and the sFlt-1 mRNA level was increased in the silencing group.

Conclusions

Downregulation of the LAMA4 gene inhibits the proliferation, migration, and invasion of EVT to suppress the expression of vascular factors, leading to the occurrence or development of preeclampsia. Our data provide new insights into modulation of LAMA4 expression as a potential target for therapy against preeclampsia. Further research is needed on placenta sampling from pre-eclamptic pregnancies to validate the effect of LAMA4 expression compared to control pregnancies.

Pyroptosis is a critical inflammatory pathway in the placenta from early onset preeclampsia and in human trophoblasts exposed to hypoxia and endoplasmic reticulum stressors

Systemic manifestation of preeclampsia (PE) is associated with circulating factors, including inflammatory cytokines and damage-associated molecular patterns (DAMPs), or alarmins. However, it is unclear whether the placenta directly contributes to the increased levels of these inflammatory triggers. Here, we demonstrate that pyroptosis, a unique inflammatory cell death pathway, occurs in the placenta predominantly from early onset PE, as evidenced by elevated levels of active caspase-1 and its substrate or cleaved products, gasdermin D (GSDMD), IL-1β, and IL-18. Using cellular models mimicking pathophysiological conditions (e.g., autophagy deficiency, hypoxia, and endoplasmic reticulum (ER) stress), we observed that pyroptosis could be induced in autophagy-deficient human trophoblasts treated with sera from PE patients as well as in primary human trophoblasts exposed to hypoxia. Exposure to hypoxia elicits excessive unfolded protein response (UPR) and ER stress and activation of the NOD-like receptor pyrin-containing 3 (NLRP3) inflammasome in primary human trophoblasts. Thioredoxin-interacting protein (TXNIP), a marker for hyperactivated UPR and a crucial signaling molecule linked to NLRP3 inflammasome activation, is significantly increased in hypoxia-treated trophoblasts. No evidence was observed for necroptosis-associated events. Importantly, these molecular events in hypoxia-treated human trophoblasts are significantly observed in placental tissue from women with early onset PE. Taken together, we propose that placental pyroptosis is a key event that induces the release of factors into maternal circulation that possibly contribute to severe sterile inflammation and early onset PE pathology.

ANXA7 regulates trophoblast proliferation and apoptosis in preeclampsia

PROBLEM

Preeclampsia (PE) is a unique gestational disorder leading to maternal and neonatal morbidity and mortality. AnnexinA7 (ANXA7) is a calcium-dependent phospholipid-binding protein that promotes membrane fusion during exocytosis. However, the function of ANXA7 in placental trophoblast is poorly understood. The present study aimed to investigate a possible association between ANXA7 and human trophoblast apoptosis.

METHODS

We collected human placental tissues from patients with PE and normal pregnant women to elucidate the expression level of ANXA7. The ANXA7-knockdown and ANXA7-overexpressing HTR8/SVneo cells were utilized for studying the function of ANXA7 in trophoblast. The proliferation and apoptosis levels of trophoblast were examined with Western blot assay, flow cytometry, Cell Counting Kit-8 assay, and immunohistochemistry.

RESULTS

ANXA7 expression was significantly lower in placentas from patients with PE patients compared with that in from normal pregnant controls. Knockdown of ANXA7 induced cell apoptosis and inhibited cell proliferation in HTR-8 via by downregulating BCL2 protein levels. Overexpression of ANXA7 reduced apoptosis and promoted HTR8 proliferation. Further analyses showed that ANXA7 knockdown inhibited the activation of the JAK1/STAT3 pathway in HTR-8 cells.

CONCLUSION

Our findings revealed a new regulatory pathway of ANXA7/JAK1/STAT3 in trophoblast apoptosis in preeclampsia, suggesting that ANXA7 is a potential therapeutic target for preeclampsia.

Placental cell death patterns exhibit differences throughout gestation in two strains of laboratory mice

Cell death is an essential physiological process required for the proper development and function of the human placenta. Although the mouse is a commonly used animal model for development studies, little is known about the extent and distribution of cell death in the mouse placenta throughout development and its physiological relevance. In the present study, we report the results of a systematic and quantitative assessment of cell death patterns in the placentae of two strains of laboratory mice commonly used for developmental studies-ICR and C57Bl/6. TUNEL staining revealed that ICR and C57Bl/6 placentae exhibited similar cell death patterns to those reported in human placentae during pregnancy, with comparatively infrequent death observed during early gestation, which increased and became more organized towards term. Interestingly, when comparing strain differences, increased cell death was observed in almost all regions of the inbred C57Bl/6 placentae compared to the outbred ICR strain. Finally, since Bcl-2 ovarian killer (Bok) has been reported to be a key player in human placental cell death, we examined its expression in murine placentae throughout gestation. Bok protein expression was observed in all placental regions and increased towards term in both strains. The results of this study indicate that although strain-specific differences in placental cell death exist, the overall rates and patterns of cell death during murine placentation parallel those previously described in humans. Thus, the murine placenta is a useful model to investigate molecular pathways involved in cell death signaling during human placentation.

Ligustroflavone reduces necroptosis in rat brain after ischemic stroke through targeting RIPK1/RIPK3/MLKL pathway

Receptor-interacting protein kinase 1/3 (RIPK1/3) and mixed lineage kinase domain-like (MLKL)-mediated necroptosis contributes to brain injury after ischemic stroke. Ligustroflavone is an ingredient of common privet with activities of anti-inflammation and complement inhibition. This study aims to explore the effect of ligustroflavone on ischemic brain injury in stroke rat and the underlying mechanisms. A rat model of ischemic stroke was established by middle cerebral artery occlusion (MCAO), which showed ischemic injury (increase in neurological deficit score and infarct volume) and upregulation of necroptosis-associated proteins (RIPK1, RIPK3 and MLKL/p-MLKL). Administration of ligustroflavone (30 mg/kg, i.g.) 15 min before ischemia evidently improved neurological function, reduced infarct volume, and decreased the levels of necroptosis-associated proteins except the RIPK1. Consistently, hypoxia-cultured PC12 cells (O₂/N2/CO₂, 1:94:5, 8 h) caused cellular injury (LDH release and necroposis) concomitant with up-regulation of necroptosis-associated proteins, and these phenomena were blocked in the presence of ligustroflavone (25 μM) except the elevated RIPK1 levels. Using the Molecular Operating Environment (MOE) program, we identified RIPK1, RIPK3, and MLKL as potential targets of ligustroflavone. Further studies showed that the interaction between RIPK3 and RIPK1 or MLKL was significantly enhanced, which was blocked in the presence of ligustroflavone. Based on these observations, we conclude that ligustroflavone protects rat brain from ischemic injury, and its beneficial effect is related to the prevention of necroptosis through a mechanism involving targeting RIPK1, RIPK3, and/or MLKL.

Placental Expression of NEMO Protein in Normal Pregnancy and Preeclampsia

Background

Preeclamptic pregnancies often present an intensified inflammatory state associated with the nuclear activity of NFκB. NEMO is an essential regulator of nuclear factor kappa B (NFκB) in cytoplasmic and nuclear cellular compartments. The aim of the present study is to examine the level and localization of the NEMO protein in preeclamptic and nonpreeclamptic placentas.

Methods

The study includes 97 preeclamptic cases and 88 controls. NEMO distribution was analyzed immunohistochemically. Its localization in the nuclear and cytoplasmic fractions, as well as in total homogenates of placental samples, was studied by western blot and ELISA.

Results

The western blot and ELISA results indicate a significant difference in NEMO concentration in the total and nuclear fractions between preeclamptic and control samples (p < 0.01 and p < 0.001, respectively). In the cytoplasmic complement, similar levels of NEMO were found in preeclamptic and control placentas. In addition, immunohistochemical staining revealed that the NEMO protein is mainly localized in the syncytiotrophoblast layer, with controls demonstrating a stronger reaction with NEMO antibodies. This study also shows that the placental level of NEMO depends on the sex of the fetus.

Conclusions

The depletion of the NEMO protein in the cellular compartments of placental samples may activate one of the molecular pathways influencing the development of preeclampsia, especially in pregnancies with a female fetus. A reduction of the NEMO protein in the nuclear fraction of preeclamptic placentas may intensify the inflammatory state characteristic for preeclampsia and increase the level of apoptosis and necrosis within preeclamptic placentas.

The trophoblast survival capacity in preeclampsia

BACKGROUND

Preeclampsia has become the world's major maternal health problem putting a huge burden on mothers, newborns and also on the health systems. The pathogenesis of preeclampsia seems to include events in very early pregnancy affecting differentiation of placental villous trophoblast. The arising changes of the cell death spectrum from apoptosis via increased autophagy and aponecrosis to necrosis in turn induce systemic inflammation of the mother.

METHODS

Placental tissue samples and maternal serum samples from 40 pregnant women were collected from normal pregnancy, IUGR, early-onset and late-onset preeclampsia. Immunohistochemistry for LC3B and Beclin-1 was quantified using systematic random sampling techniques. Serum levels of LDH and other markers were assessed in serum.

RESULTS

Expression of the autophagy markers LC3B and Beclin-1 was significantly different between groups as was the LC3B/Beclin-1 ratio. Early-onset preeclampsia and IUGR had the highest autophagy protein expression levels, while normal pregnancy and late-onset preeclampsia had the highest LC3B/Beclin-1 ratio. Early-onset preeclampsia had the highest negative correlation with free LDH as cell defect marker.

CONCLUSIONS

Autophagy plays a critical role in the cell death spectrum and cellular survival capacity of villous trophoblast. Alterations in autophagic protein expression are involved in pathological pregnancies such as preeclampsia.

Death by over-eating: The Gaucher disease associated gene GBA1, identified in a screen for mediators of autophagic cell death, is necessary for developmental cell death in Drosophila midgut

Autophagy is critical for homeostasis and cell survival during stress, but can also lead to cell death, a little understood process that has been shown to contribute to developmental cell death in lower model organisms, and to human cancer cell death. We recently reported ¹ on our thorough molecular and morphologic characterization of an autophagic cell death system involving resveratrol treatment of lung carcinoma cells. To gain mechanistic insight into this death program, we performed a signalome-wide RNAi screen for genes whose functions are necessary for resveratrol-induced death. The screen identified GBA1, the gene encoding the lysosomal enzyme glucocerebrosidase, as an important mediator of autophagic cell death. Here we further show the physiological relevance of GBA1 to developmental cell death in midgut regression during Drosophila metamorphosis. We observed a delay in midgut cell death in two independent Gba1a RNAi lines, indicating the critical importance of Gba1a for midgut development. Interestingly, loss-of-function GBA1 mutations lead to Gaucher Disease and are a significant risk factor for Parkinson Disease, which have been associated with defective autophagy. Thus GBA1 is a conserved element critical for maintaining proper levels of autophagy, with high levels leading to autophagic cell death.