Roles of apolipoprotein E (ApoE) and inducible nitric oxide synthase (iNOS) in inflammation and apoptosis in preeclampsia pathogenesis and progression

The role of the placenta-brain axis in psychoneuroimmune programming

Gestational exposures have enduring impacts on brain and neuroimmune development and function. Perturbations of pregnancy leading to placental structure/function deficits, cell stress, immune activation, and endocrine changes (metabolic, growth factors, etc.) all increase neuropsychiatric risk in offspring. The existing literature links obstetric diseases with placental involvement to offspring neuroimmune outcomes and neurodevelopmental risk. Psychoneuroimmune outcomes in offspring brain include changes to microglia, cytokine/chemokine production, cell stress, and long-term immunoreactivity. These outcomes are altered by structural, anti-angiogenic/hypoxic, inflammatory, and metabolic diseases of the placenta. This fetal programming occurs via direct placental passage or production of factors which can act directly on fetal brain substrates, or indirectly via action of circulating factors on intermediates in the placenta. Placental neuroendocrine, vascular/angiogenic, immune, and extracellular vesicular mechanisms are detailed. These mechanisms interact within various placental and pregnancy conditions. An increased understanding of the placental origins of psychoneuroimmunology will yield dividends for human health. Identifying maternal and placental biomarkers for fetal neuroimmune health may also revolutionize early diagnosis and precision psychiatry, empowering patients to make the best healthcare decisions for their families. Targeting placental mechanisms may be a valuable approach for the prevention and mitigation of intergenerational, lifelong neuropathology.

Maternal Exercise Prior to and during Gestation Induces Sex-Specific Alterations in the Mouse Placenta

While exercise (EX) during pregnancy is beneficial for both mother and child, little is known about the mechanisms by which maternal exercise mediates changes in utero. Six-week-old female C57BL/6 mice were divided into two groups: with (exercise, EX; N = 7) or without (sedentary, SED; N = 8) access to voluntary running wheels. EX was provided via 24 h access to wheels for 10 weeks prior to conception until late pregnancy (18.5 days post coitum). Sex-stratified placentas and fetal livers were collected. Microarray analysis of SED and EX placentas revealed that EX affected gene transcript expression of 283 and 661 transcripts in male and female placentas, respectively (±1.4-fold, p < 0.05). Gene Set Enrichment and Ingenuity Pathway Analyses of male placentas showed that EX led to inhibition of signaling pathways, biological functions, and down-regulation of transcripts related to lipid and steroid metabolism, while EX in female placentas led to activation of pathways, biological functions, and gene expression related to muscle growth, brain, vascular development, and growth factors. Overall, our results suggest that the effects of maternal EX on the placenta and presumably on the offspring are sexually dimorphic.

Activation of endothelial NO synthase and P2X7 receptor modification mediates the cholinergic control of ATP-induced interleukin-1β release by mononuclear phagocytes

Objective

The pro-inflammatory cytokine interleukin-1β (IL-1β) plays a central role in host defense against infections. High systemic IL-1β levels, however, promote the pathogenesis of inflammatory disorders. Therefore, mechanisms controlling IL-1β release are of substantial clinical interest. Recently, we identified a cholinergic mechanism inhibiting the ATP-mediated IL-1β release by human monocytes via nicotinic acetylcholine receptor (nAChR) subunits α7, α9 and/or α10. We also discovered novel nAChR agonists that trigger this inhibitory function in monocytic cells without eliciting ionotropic functions at conventional nAChRs. Here, we investigate the ion flux-independent signaling pathway that links nAChR activation to the inhibition of the ATP-sensitive P2X7 receptor (P2X7R).

Methods

Different human and murine mononuclear phagocytes were primed with lipopolysaccharide and stimulated with the P2X7R agonist BzATP in the presence or absence of nAChR agonists, endothelial NO synthase (eNOS) inhibitors, and NO donors. IL-1β was measured in cell culture supernatants. Patch-clamp and intracellular Ca2+ imaging experiments were performed on HEK cells overexpressing human P2X7R or P2X7R with point mutations at cysteine residues in the cytoplasmic C-terminal domain.

Results

The inhibitory effect of nAChR agonists on the BzATP-induced IL-1β release was reversed in the presence of eNOS inhibitors (L-NIO, L-NAME) as well as in U937 cells after silencing of eNOS expression. In peripheral blood mononuclear leukocytes from eNOS gene-deficient mice, the inhibitory effect of nAChR agonists was absent, suggesting that nAChRs signal via eNOS to inhibit the BzATP-induced IL-1β release. Moreover, NO donors (SNAP, S-nitroso-N-acetyl-DL-penicillamine; SIN-1) inhibited the BzATP-induced IL-1β release by mononuclear phagocytes. The BzATP-induced ionotropic activity of the P2X7R was abolished in the presence of SIN-1 in both, Xenopus laevis oocytes and HEK cells over-expressing the human P2X7R. This inhibitory effect of SIN-1 was absent in HEK cells expressing P2X7R, in which C377 was mutated to alanine, indicating the importance of C377 for the regulation of the P2X7R function by protein modification.

Conclusion

We provide first evidence that ion flux-independent, metabotropic signaling of monocytic nAChRs involves eNOS activation and P2X7R modification, resulting in an inhibition of ATP signaling and ATP-mediated IL-1β release. This signaling pathway might be an interesting target for the treatment of inflammatory disorders.

Evaluation of the PLAC8 Gene in Mexican Women With and Without Preeclampsia and Obesity

Preeclampsia (PE) is a leading cause of maternal-fetal mortality worldwide, and obesity is an important risk factor. Genes associated with pathophysiological events common to preeclampsia and obesity, such as PLAC8, remain to be studied; therefore, the aim of the present study was to evaluate this gene in the placentas of women affected with preeclampsia and healthy pregnant women. This case-controlled study included 71 healthy and 64 preeclampsia pregnancies. Gene expression was evaluated in primary human cytotrophoblasts (PHCT) from six normal and six preeclampsia pregnancies, and protein expression was verified in placentas from five healthy and six preeclampsia pregnancies. The whole coding and 5′ regions of the PLAC8 gene were sequenced from healthy (n = 10) and preeclamptic (n = 10) pregnancies. The presence of the observed nucleotide variations was analyzed by RT-PCR in the total population. Statistical analyses were performed accordingly. Obesity was associated with severe preeclampsia (SPE) (OR = 3.34; CI 95% 1.3–8.2, p < 0.01). Significantly higher mRNA and protein expression was observed in preeclamptic vs. healthy placentas (p < 0.05). After sequencing, a single nucleotide variation was identified in 10 cases and one control (p < 0.01), which was then evaluated in the total population showing no association with preeclampsia. This preliminary study confirms the association of SPE with obesity and suggests higher expression of PLAC8 mRNA and protein in placentas from preeclampsia. No differences in nucleotide variations between cases and controls of the whole population were observed. Further research is required to evaluate the implications of higher gene/protein expression in preeclampsia and the causes of such variation.

Placenta-derived macaque trophoblast stem cells: differentiation to syncytiotrophoblasts and extravillous trophoblasts reveals phenotypic reprogramming

Nonhuman primates are excellent models for studying human placentation as experimental manipulations in vitro can be translated to in vivo pregnancy. Our objective was to develop macaque trophoblast stem cells (TSCs) as an in vitro platform for future assessment of primate trophoblast development and function. Macaque TSC lines were generated by isolating first and second trimester placental villous cytotrophoblasts followed by culture in TSC medium to maintain cellular proliferation. TSCs grew as mononuclear colonies, whereas upon induction of syncytiotrophoblast (ST) differentiation multinuclear structures appeared, indicative of syncytium formation. Chorionic gonadotropin secretion was > 4000-fold higher in ST culture media compared to TSC media. The secretion of chorionic gonadotropin by TSC-derived ST reflects a reprogramming of macaque TSCs to an earlier pregnancy phenotype. Characteristic trophoblast hallmarks were defined in TSCs and ST including expression of C19MC miRNAs and the macaque placental nonclassical MHC class I molecule, Mamu-AG. Extravillous trophoblasts (EVTs) were derived that express macaque EVT markers Mamu-AG and CD56, and also secrete high levels of MMP2. Our analyses of macaque TSCs suggests that these cells represent a proliferative, self-renewing population capable of differentiating to STs and EVTs in vitro thereby establishing an experimental model of primate placentation.

Cardiovascular bioimaging of nitric oxide: Achievements, challenges, and the future

Nitric oxide (NO) is a ubiquitous, volatile, cellular signaling molecule that operates across a wide physiological concentration range (pM-µM) in different tissues. It is a highly diffusible messenger and intermediate in various metabolic pathways. NO plays a pivotal role in maintaining optimum cardiovascular function, particularly by regulating vascular tone and blood flow. This review highlights the need for accurate, real-time bioimaging of NO in clinical diagnostic, therapeutic, monitoring, and theranostic applications within the cardiovascular system. We summarize electrochemical, optical, and nanoscale sensors that allow measurement and imaging of NO, both directly and indirectly via surrogate measurements. The physical properties of NO render it difficult to accurately measure in tissues using direct methods. There are also significant limitations associated with the NO metabolites used as surrogates to indirectly estimate NO levels. All these factors added to significant variability in the measurement of NO using available methodology have led to a lack of sensors and imaging techniques of clinical applicability in relevant vascular pathologies such as atherosclerosis and ischemic heart disease. Challenges in applying current methods to biomedical and clinical translational research, including the wide physiological range of NO and limitations due to the characteristics and toxicity of the sensors are discussed, as are potential targets and modifications for future studies. The development of biocompatible nanoscale sensors for use in combination with existing clinical imaging modalities provides a feasible opportunity for bioimaging NO within the cardiovascular system.

CD30 Is Highly Expressed in Chronic Obstructive Pulmonary Disease and Induces the Pulmonary Vascular Remodeling

Chronic obstructive pulmonary disease (COPD) is one of the common and underdiagnosed diseases with the highest morbidity and mortality in the world. The development of COPD can lead to pulmonary vascular remodeling and pulmonary hypertension, further causing the occurrence of pulmonary heart disease. Therefore, attenuation of pulmonary vascular remodeling and pulmonary hypertension caused by COPD can significantly delay cardiovascular complications. In the study, we firstly found that the expression of CD30 and CD30L was increased in COPD. Importantly, the serum CD30L levels were significantly higher in patients with stable COPD relative to those with acute exacerbation of COPD (AECOPD). This suggested that CD30 might be related to the development of COPD. In addition, we found that the expression of CD30 in the COPD rat model was significantly increased compared with control group. And treatment with the anti-CD30 antibody reduced the serum concentration and tissue expression of CD30 in rat. Importantly, anti-CD30 antibody alleviated pulmonary vascular remodeling in COPD model rats. This suggested that CD30 played an important role in the course of COPD. Finally, we found that, in the HPASMC and HPAEC cell lines, CD30 can affect the cell viability and cell migration and inhibited hypoxia-induced cell apoptosis in a concentration-dependent manner. We also found CD30 induced extracellular matrix formation through decreasing the expression of MMP-2, thus promoting the pulmonary vascular remodeling. The study indicated that CD30 and CD30L were involved in pulmonary vascular remodeling and inflammatory response in COPD. Altogether, CD30 might be a marker for the early diagnosis and progression of COPD.

Lipid profile, plasma apolipoproteins, and pre-eclampsia risk in the GenPE case-control study

BACKGROUND AND AIMS

Pre-eclampsia constitutes a leading cause of maternal and perinatal morbidity and mortality. Pre-eclampsia susceptibility is believed to be associated with altered lipid profiles and abnormal lipid metabolism via lipid peroxidation that leads to endothelial dysfunction. The goal of this study was to evaluate the association of maternal blood lipid and apolipoprotein levels with pre-eclampsia in a large-scale study.

METHODS

Using data from a large case-control study (1366 cases of pre-eclampsia and 1741 normotensive controls), the association between the distributions of eight lipid fractions and pre-eclampsia risk was evaluated using adjusted logistic regression models. Pre-eclampsia was defined as blood pressure ≥140/90 mmHg and proteinuria ≥300 mg/24 h (>1 + dipstick). Sub-group analyses were conducted for early (<34 weeks) and late (≥37 weeks) pre-eclampsia, estimating the effect of 1 standard deviation increase in log-transformed lipid fraction levels in adjusted multinomial regression models.

RESULTS

After adjustment for potential confounders, concentrations of triglycerides, apolipoprotein E (ApoE) and the relationship between apolipoprotein B and A1 (ApoB/ApoA1) showed the strongest associations with pre-eclampsia, particularly for those cases with an early onset.

CONCLUSIONS

Higher levels of triglycerides, ApoE and the ApoB/ApoA1 ratio are associated with an increased risk of pre-eclampsia. Further studies that allow for a causal inference are needed to confirm or refute the aetiological role of blood lipids in pre-eclampsia.

Preeclampsia is associated with hypermethylation of IGF-1 promoter mediated by DNMT1

Previous studies have demonstrated a dynamic epigenetic regulation of genes expression in placenta trophoblasts and a dynamic imbalance of DNA methylation and hydroxymethylation. Reduced IGF-1 has been observed in preeclampsia. This study was to investigate the interactive roles between IGF-1 and the global DNA methylation/hydroxymethylation, and the status of DNA methylation/hydroxymethylation and associated enzymes such as DNMTs and TETs in peeeclamptic placentas and hypoxic trophoblasts. It was found that IGF-1 was decreased in preeclamptic placentas and hypoxic trophoblasts when compared to the control group using immunohistochemisty, western blot, qRT-PCR and ELISA. Pyrophosphate sequencing showed IGF-1 promoter was significantly hypermethylated in preeclamptic placentas, which was responsible for reduced IGF-1 expression. Preeclamptic placentas and hypoxic trophoblasts were hypermethylated and hypohydroxymethylated accompanied by remarkably higher 5mC, DNMT1 and DNMT3b, and lower DNMT3a, 5hmC, TET1, TET2 and TET3 detected by immunohistochemisty, western blot, qRT-PCR and ELISA. Pearson's correlation confirmed a statistically significant negative correlation between IGF-1 and DNMT1. Furthermore, both treatment with 5-Aza-dc and DNMT1-siRNA significantly increased the expression of IGF-1 in HTR8 cells, indicating the potential mechanism of DNMT1-mediated DNA methylation in IGF-1 regulation. However, IGF-1 didn't change DNA methylation or hydroxymethylation. These findings suggest that preeclampsia is associated with hypermethylation of IGF-1 promoter mediated by DNMT1 and provide new insights into the diagnosis and treatment of preeclampsia.

Genetic Approaches in Preeclampsia

Preeclampsia (PE) is a serious hypertensive disorder that affects up to 8% of all pregnancies annually. An established risk factor for PE is family history, clearly demonstrating an underlying genetic component to the disorder. To date, numerous genetic studies, using both the candidate gene and genome-wide approach, have been undertaken to tease out the genetic basis of PE and understand its origins. Such studies have identified some promising candidate genes such as STOX1 and ACVR2A. Nevertheless, researchers face ongoing challenges of replicating these genetic associations in different populations and performing the functional validation of identified genetic variants to determine their causality in the disorder. This chapter will review the genetic approaches used in the study of PE, discuss their limitations and possible confounders, and describe current strategies.

Hypoxia-induced miR-210 promoter demethylation enhances proliferation, autophagy and angiogenesis of schwannoma cells

Hypoxia, a dominant feature in cancer occurrence and evolution, exists throughout the progression of most malignant tumors. This study focused on the mechanism of hypoxia-induced miR-210 upregulation, and the miR-210 functions in schwannoma. We detected microvascular density, vascular endothelial growth factor (VEGF) and miR-210 expression levels using schwannoma tissue mciroarray. The results showed that miR-210 expression was significantly associated with VEGF. Moreover, the cytological tests showed that hypoxia induced miR-210 expression, while reduce ephrin-A3 expression. The bisulfate genomic sequencing PCR results showed that miR-210 promoter region was hypermethylated in RT4-D6P2T in normoxia, while demethylated in hypoxia, and the region included the hypoxia-inducible factor-1α (HIF-1α) response element site. Cellular function research showed that hypoxia resulted in RT4-D6P2T apoptosis, higher autophage and invasion. Besides, hypoxia can affect HIF-1α/VEGF-mediated angiogenesis. To learn about the specific functions of miR-210, we found that with miR-210 inhibition, tumor cell apoptosis increased, autophagy and angiogenesis reduced, and the cell cycle was arrested. Hypoxia promoted miR-210 expression through promoter demethylation, then consequently enhanced tumor cell proliferation and autophagy, increasing tumor cell angiogenesis. Thus, miR-210 could be a potential marker for judging tumor malignancy and be taken as an effective target for clinical auxiliary treatment of neurilemmoma.

Citrus hallabong [(Citrus unshiu × C. sinensis) × C. reticulata)] exerts potent anti-inflammatory properties in murine splenocytes and TPA-induced murine ear oedema model

CONTEXT

Hallabong [(Citrus unshiu × C. sinensis) X C. reticulata)] (Rutaceae) is a hybrid citrus cultivated in temperate regions of South Korea. Its fruit is well-known for pharmacological properties.

OBJECTIVE

This study examined the anti-inflammatory effect of 80% ethanol extract of Hallabong (HE) on concanavalin A (Con A)-stimulated splenocytes and mouse oedema model induced by 12-O-tetradecanoylphorbal acetate (TPA).

MATERIALS AND METHODS

Murine splenocytes treated with HE were stimulated with Con A (10 μg/mL, for 24 h) were evaluated for T-cell population and production of inflammatory cytokines IL-2, IL-4 and IFN-γ. Anti-inflammatory effect of topically applied HE (100 μg/20 μL) on TPA (4 μg/20 μL/ear)-induced ear oedema was investigated in mouse model.

RESULTS

HE-treated Con A-stimulated murine splenocytes showed a marked decrease in CD44/CD62L⁺ memory T-cell population, an important marker for anti-inflammatory activity, and a significant inhibition in the production of IL-2 and IFN-γ. HE treatment had reduced the mouse skin oedema (47%) and myeloperoxidase (MPO) activity significantly (40%) in TPA-challenged tissues. More importantly, immunohistochemical localization revealed the suppressed (p < 0.05) expression of inducible nitric oxide (iNOS), cyclooxygenase-2 (COX2). HE decreased the infiltration of CD3⁺ T cells and F4/80⁺ macrophages to the site of inflammation and a topical application of HE significantly suppressed the expression of TNF-α (20.2%).

DISCUSSION AND CONCLUSION

A topical application of HE can exert a potential anti-inflammatory effect and HE can be explored further as a putative alternative therapeutic agent for inflammatory oedema.

Modulation of FABP4 hypomethylation by DNMT1 and its inverse interaction with miR-148a/152 in the placenta of preeclamptic rats and HTR-8 cells

Inflammation and dysregulated lipid metabolism are involved in the pathogenesis of preeclampsia, and fatty acid binding protein 4 (FABP4) is known to regulate both inflammation and lipid metabolism. In the present study, we elucidated the role of FABP4 using in vitro and in vivo models of preclampsia. We found increased expression of FABP4 in the placenta of preeclamptic rats, which was further confirmed in HTR-8 cells, an extravillous trophoblast cell line, treated with L-NAME. Overexpression of FABP4 in HTR-8 cells resulted in upregulated expression of pro-inflammatory cytokines IL-6 and TNF-α, and increased lipid accumulation, suggesting that FABP4 plays a role in preeclampsia. Furthermore, downregulation of methylation in the promotor resulted in increased FABP4 expression, which was mediated by downregulated DNA methyltransferase 1 (DNMT1). Bioinformatics analysis showed that miR-148a/152 regulated the expression of DNMT1, and additional in vitro studies revealed that miR-148a/152 inhibited DNMT1 expression by directly binding to its 3'-UTR. Interestingly, DNMT1 enhanced the expression of miR-148a/152 by downregulation of methylation in its promotor. Taken together, our results showed that FABP4 may be involved in the pathogenesis of preeclampsia, and the expression of FABP4 is enhanced by miR-148a/152 mediated inhibition of DNMT1 expression.

Increased risk for the development of preeclampsia in obese pregnancies: weighing in on the mechanisms

Preeclampsia (PE) is a pregnancy-specific disorder typically presenting as new-onset hypertension and proteinuria. While numerous epidemiological studies have demonstrated that obesity increases the risk of PE, the mechanisms have yet to be fully elucidated. Growing evidence from animal and human studies implicate placental ischemia in the etiology of this maternal syndrome. It is thought that placental ischemia is brought about by dysfunctional cytotrophoblast migration and invasion into the uterus and subsequent lack of spiral arteriole widening and placental perfusion. Placental ischemia/hypoxia stimulates the release of soluble placental factors into the maternal circulation where they cause endothelial dysfunction, particularly in the kidney, to elicit the clinical manifestations of PE. The most recognized of these factors are the anti-angiogenic sFlt-1 and pro-inflammatory TNF-α and AT1-AA, which promote endothelial dysfunction by reducing levels of the provasodilator nitric oxide and stimulating production of the potent vasoconstrictor endothelin-1 and reactive oxygen species. We hypothesize that obesity-related metabolic factors increase the risk for developing PE by impacting various stages in the pathogenesis of PE, namely, 1) cytotrophoblast migration and placental ischemia; 2) release of soluble placental factors into the maternal circulation; and 3) maternal endothelial and vascular dysfunction. This review will summarize the current experimental evidence supporting the concept that obesity and metabolic factors like lipids, insulin, glucose, and leptin affect placental function and increase the risk for developing hypertension in pregnancy by reducing placental perfusion; enhancing placental release of soluble factors; and by increasing the sensitivity of the maternal vasculature to placental ischemia-induced soluble factors.

Combined elevated midpregnancy tumor necrosis factor alpha and hyperlipidemia in pregnancies resulting in early preterm birth

OBJECTIVE

The objective of the study was to determine whether pregnancies resulting in early preterm birth (PTB) (<30 weeks) were more likely than term pregnancies to have elevated midtrimester serum tumor necrosis factor alpha (TNF-α) levels combined with lipid patterns suggestive of hyperlipidemia.

STUDY DESIGN

In 2 nested case-control samples drawn from California and Iowa cohorts, we examined the frequency of elevated midpregnancy serum TNF-α levels (in the fourth quartile [4Q]) and lipid patterns suggestive of hyperlipidemia (eg, total cholesterol, low-density-lipoproteins, or triglycerides in the 4Q, high-density lipoproteins in the first quartile) (considered independently and by co-occurrence) in pregnancies resulting in early PTB compared with those resulting in term birth (n = 108 in California and n = 734 in Iowa). Odds ratios (ORs) and 95% confidence intervals (CIs) estimated in logistic regression models were used for comparisons.

RESULTS

Early preterm pregnancies were 2-4 times more likely than term pregnancies to have a TNF-α level in the 4Q co-occurring with indicators of hyperlipidemia (37.5% vs 13.9% in the California sample (adjusted OR, 4.0; 95% CI, 1.1-16.3) and 26.3% vs 14.9% in the Iowa sample (adjusted OR, 2.7; 95% CI, 1.1-6.3). No differences between early preterm and term pregnancies were observed when TNF-α or target lipid abnormalities occurred in isolation. Observed differences were not explicable to any maternal or infant characteristics.

CONCLUSION

Pregnancies resulting in early PTB were more likely than term pregnancies to have elevated midpregnancy TNF-α levels in combination with lipid patterns suggestive of hyperlipidemia.