Interferon-α and angiogenic dysregulation in pregnant lupus patients who develop preeclampsia

Dysfunction of endothelial progenitor cells is associated with the type I IFN pathway in patients with polymyositis and dermatomyositis

OBJECTIVE

Alterations in phenotype and function of endothelial progenitor cells (EPCs) have been associated with poor vascular outcomes and impaired vascular repair in various conditions. Our hypothesis was that patients with PM and DM have dysregulation of EPCs driven by type I IFN and IL-18 similar to other autoimmune diseases.

METHODS

Quantification of circulating EPCs was performed by flow cytometry in patients with PM/DM and matched healthy controls. The ability of EPCs to differentiate into mature endothelial cells was investigated by light and fluorescence microscopy quantification in the presence or absence of PM/DM or control serum, neutralizing antibodies to type I IFN receptor or IL-18. Serum type I IFN activity was quantified by induction of type I IFN-inducible genes in HeLa cells. Circulating IL-18 concentrations were assessed by ELISA.

RESULTS

Circulating EPCs were significantly lower in PM/DM patients compared with controls. PM/DM EPCs displayed a decreased capacity to differentiate into mature endothelial cells and PM/DM serum significantly inhibited differentiation of control EPCs. This effect was reversed in the majority of samples with neutralizing antibodies to IL-18 or to type I IFN receptor or by a combination of these antibodies. Patients with associated impairments in EPC function had higher type I IFN serum activity.

CONCLUSION

PM/DM is associated with dysregulation of EPC phenotype and function that may be attributed, at least in part, to aberrant IL-18 and type I IFN pathways. The implication of these vasculopathic findings for disease prognosis and complications remains to be determined.

Immunohistochemical Expression of Myeloperoxidase in Placental Samples of Systematic Lupus Erythematosus Pregnancies

OBJECTIVE

Reports of increased level of Myeloperoxidase (MPO) in plasma and placental extracts of Systematic Lupus Erythematosus (SLE) has been proposed that MPO may have an important role in this pregnancy complication. In present study immunohistochemical MPO expression was investigated in placental samples of SLE women compared with normal controls.

MATERIALS AND METHODS

Ten patients with SLE were recruited as case group. Control group was selected from mothers with normal uncomplicated pregnancies. A monoclonal antibody specific for MPO was used for immunohistochemical staining and then the staining was quantified and differences between groups were compared using Mann-Whitney U test.

RESULTS

There were significant differences in the expression levels of MPO in the syncytiotrophoblast cells and the extravillous trophoblast cells between the control and SLE groups (p < 0.05). There were no significant differences in the expression level of MPO in the vascular endothelium and the relative number of the MPO-positive leukocytes in placental tissue between SLE and control groups (p > 0.05).

CONCLUSION

The present study showed that MPO expression is increased in syncytiotrophoblast cells and the extravillous trophoblast cells of SLE placentas compared to healthy subjects. It seems that these changes are able to impress structure and function of placenta and survival of the fetus.

Antiphospholipid antibody-induced miR-146a-3p drives trophoblast interleukin-8 secretion through activation of Toll-like receptor 8

STUDY QUESTION

What is the role of microRNAs (miRs) in antiphospholipid antibody (aPL)-induced trophoblast inflammation?

SUMMARY ANSWER

aPL-induced up-regulation of trophoblast miR-146a-3p is mediated by Toll-like receptor 4 (TLR4), and miR-146a-3p in turn drives the cells to secrete interleukin (IL)-8 by activating the RNA sensor, TLR8.

WHAT IS KNOWN ALREADY

Obstetric antiphospholipid syndrome (APS) is an autoimmune disorder characterized by circulating aPL and an increased risk of pregnancy complications. We previously showed that aPL recognizing beta2 glycoprotein I (β2GPI) elicit human first trimester trophoblast secretion of IL-8 by activating TLR4. Since some miRs control TLR responses, their regulation in trophoblast cells by aPL and functional role in the aPL-mediated inflammatory response was investigated. miRs can be released from cells via exosomes, and therefore, miR exosome expression was also examined. A panel of miRs was selected based on their involvement with TLR signaling: miR-9; miR-146a-5p and its isomiR, miR-146a-3p; miR-155, miR-210; and Let-7c. Since certain miRs can activate the RNA sensor, TLR8, this was also investigated.

STUDY DESIGN, SIZE, DURATION

For in vitro studies, the human first trimester extravillous trophoblast cell line, HTR8 was studied. HTR8 cells transfected to express a TLR8 dominant negative (DN) were also used. Plasma was evaluated from pregnant women who have aPL, either with or without systemic lupus erythematous (SLE) (n = 39); SLE patients without aPL (n = 30); and healthy pregnant controls (n = 20).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Trophoblast HTR8 wildtype and TLR8-DN cells were incubated with or without aPL (mouse anti-human β2GPI mAb) for 48-72 h. HTR8 cells were also treated with or without aPL in the presence and the absence of a TLR4 antagonist (lipopolysaccharide from Rhodobacter sphaeroides; LPS-RS), specific miR inhibitors or specific miR mimics. miR expression levels in trophoblast cells, trophoblast-derived exosomes and exosomes isolated from patient plasma were measured by qPCR. Trophoblast IL-8 secretion was measured by ELISA.

MAIN RESULTS AND THE ROLE OF CHANCE

aPL significantly increased trophoblast cellular and exosome expression of miR-146a-5p, miR-146a-3p, miR-155 and miR-210. aPL-induced up-regulation of trophoblast miR-146a-5p, miR-146a-3p and miR-210, but not miR-155, was inhibited by the TLR4 antagonist, LPS-RS. While inhibition or overexpression of miR-146a-5p had no effect on aPL-induced trophoblast IL-8 secretion, miR-146a-3p inhibition significantly reduced this response. aPL-induced trophoblast IL-8 secretion was inhibited by the presence of the TLR8-DN. In the absence of aPL, transfection of trophoblast cells with a miR-146a-3p mimic significantly increased IL-8 secretion and this was inhibited by the presence of the TLR8-DN. Patients with aPL and adverse pregnancy outcomes (APOs) expressed significantly higher levels of circulating miR-146a-3p compared with healthy pregnant controls with no pregnancy complications (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

While the enrichment of miR-146a-3p in trophoblast-derived exosomes support the role of this miR acting in a paracrine or endocrine manner through exosome delivery, this has not been demonstrated. However, miR-146a-3p may also exert its pro-inflammatory effect intracellularly within the same trophoblast cell targeted by aPL.

WIDER IMPLICATIONS OF THE FINDINGS

These findings provide a novel mechanism of trophoblast inflammation through miRs activating RNA-sensing receptors. Furthermore, circulating exosomal-associated miR-146a-3p in APS patients may serve clinically as a biomarker for related APOs.

STUDY FUNDING/COMPETING INTERESTS

This study was supported in part by grants from the American Heart Association (#10GRNT3640032 to V.M.A.), the March of Dimes Foundation (Gene Discovery and Translational Research Grant #6-FY12-255 to V.M.A.), NICHD, NIH (R01HD049446 to V.M.A.), the Gina M. Finzi Memorial Student Summer Fellowship from the Lupus Foundation of America (to S.M.G.), and the Yale University School of Medicine Medical Student Fellowship (to S.M.G.). The authors declare no competing financial interests.

TRIAL REGISTRATION NUMBER

N/A.

Endothelial cell dysfunction and cardiac hypertrophy in the STOX1 model of preeclampsia

Preeclampsia is a disease of pregnancy involving systemic endothelial dysfunction. However, cardiovascular consequences of preeclampsia are difficult to analyze in humans. The objective of the present study is to evaluate the cardiovascular dysfunction induced by preeclampsia by examining the endothelium of mice suffering of severe preeclampsia induced by STOX1 overexpression. Using Next Generation Sequencing on endothelial cells of mice carrying either transgenic or control embryos, we discovered significant alterations of gene networks involved in inflammation, cell cycle, and cardiac hypertrophy. In addition, the heart of the preeclamptic mice revealed cardiac hypertrophy associated with histological anomalies. Bioinformatics comparison of the networks of modified genes in the endothelial cells of the preeclamptic mice and HUVECs exposed to plasma from preeclamptic women identified striking similarities. The cardiovascular alterations in the pregnant mice are comparable to those endured by the cardiovascular system of preeclamptic women. The STOX1 mice could help to better understand the endothelial dysfunction in the context of preeclampsia, and guide the search for efficient therapies able to protect the maternal endothelium during the disease and its aftermath.

Angiogenic factor imbalance early in pregnancy predicts adverse outcomes in patients with lupus and antiphospholipid antibodies: results of the PROMISSE study

BACKGROUND

Over 20% of pregnancies in patients with systemic lupus erythematosus (SLE) and/or antiphospholipid antibodies (APL) result in an adverse pregnancy outcome (APO) related to abnormal placentation. The ability to identify, early in pregnancy, patients who are destined for poor outcomes would significantly impact care of this high-risk population. In nonautoimmune patients, circulating angiogenic factors are dysregulated in disorders of placentation, such as preeclampsia (PE) and fetal growth restriction.

OBJECTIVE

We sought to determine whether early dysregulation of circulating angiogenic factors can predict APO in high-risk SLE and/or APL pregnancies.

STUDY DESIGN

We used data and samples from the Predictors of Pregnancy Outcome: Biomarkers in APL Syndrome and SLE (PROMISSE), a multicenter prospective study that enrolled 492 pregnant women with SLE and/or APL from September 2003 through August 2013. Patients were followed through pregnancy from <12 weeks gestation. Circulating levels of soluble fms-like tyrosine kinase-1 (sFlt1), placental growth factor (PlGF), and soluble endoglin were measured monthly and subjects followed up for APO, classified as severe (PE <34 weeks, fetal/neonatal death, indicated preterm delivery <30 weeks) or moderate (PE ≥34 weeks, indicated preterm delivery 30-36 weeks, growth restriction without PE).

RESULTS

Severe APOs occurred in 12% and moderate APOs in 10% of patients. By 12-15 weeks, sFlt1, PlGF, and soluble endoglin levels were markedly altered in women who developed severe APO. After adjusting for clinical risk factors, sFlt1 was the strongest predictor of severe APO among 12-15 week measures (odds ratio, 17.3 comparing highest and lowest quartiles; 95% confidence interval [CI], 3.5-84.8; positive predictive value [PPV], 61%; negative predictive value [NPV], 93%). At 16-19 weeks, the combination of sFlt1 and PlGF was most predictive of severe APO, with risk greatest for subjects with both PlGF in lowest quartile (<70.3 pg/mL) and sFlt1 in highest quartile (>1872 pg/mL; odds ratio, 31.1; 95% CI, 8.0-121.9; PPV, 58%; NPV, 95%). Severe APO rate in this high-risk subgroup was 94% (95% CI, 70-99.8%), if lupus anticoagulant or history of high blood pressure was additionally present. In contrast, among patients with both sFlt1 <1872 pg/mL and PlGF >70.3 pg/mL, rate of severe APO was only 4.6% (95% CI, 2.1-8.6%).

CONCLUSION

Circulating angiogenic factors measured during early gestation have a high NPV in ruling out the development of severe adverse outcomes among patients with SLE and/or APL syndrome. Timely risk stratification of patients is important for effective clinical care and optimal allocation of health care resources.

Why is placentation abnormal in preeclampsia?

The causes of preeclampsia remain one of the great medical mysteries of our time. This syndrome is thought to occur in 2 stages with abnormal placentation leading to a maternal inflammatory response. Specific regions of the placenta have distinct pathologic features. During normal pregnancy, cytotrophoblasts emigrate from the chorionic villi and invade the uterus, reaching the inner third of the myometrium. This unusual process is made even more exceptional by the fact that the placental cells are hemiallogeneic, coexpressing maternal and paternal genomes. Within the uterine wall, cytotrophoblasts deeply invade the spiral arteries. Cytotrophoblasts migrate up these vessels and replace, in a retrograde fashion, the maternal endothelial lining. They also insert themselves among the smooth muscle cells that form the tunica media. As a result, the spiral arteries attain the physiologic properties that are required to perfuse the placenta adequately. In comparison, invasion of the venous side of the uterine circulation is minimal, sufficient to enable venous return. In preeclampsia, cytotrophoblast invasion of the interstitial uterine compartment is frequently shallow, although not consistently so. In many locations, spiral artery invasion is incomplete. There are many fewer endovascular cytotrophoblasts, and some vessels retain portions of their endothelial lining with relatively intact muscular coats, although others are not modified. Work from our group showed that these defects mirror deficits in the differentiation program that enables cytotrophoblast invasion of the uterine wall. During normal pregnancy, invasion is accompanied by the down-regulation of epithelial-like molecules that are indicative of their ectodermal origin and up-regulation of numerous receptors and ligands that typically are expressed by endothelial or vascular smooth muscle cells. For example, the expression of epithelial-cadherin (the cell-cell adhesion molecule that many ectodermal derivatives use to adhere to one another) becomes nearly undetectable, replaced by vascular-endothelial cadherin, which serves the same purpose in blood vessels. Invading cytotrophoblasts also modulate vascular endothelial growth factor ligands and receptors, at some point in the differentiation process expressing every (mammalian) family member. Molecules in this family play crucial roles in vascular and trophoblast biology, including the prevention of apoptosis. In preeclampsia, this process of vascular mimicry is incomplete, which we theorize hinders the cells interactions with spiral arterioles. What causes these aberrations? Given what is known from animal models and human risk factors, reduced placental perfusion and/or certain disease states (metabolic, immune and cardiovascular) lie upstream. Recent evidence suggests the surprising conclusion that isolation and culture of cytotrophoblasts from the placentas of pregnancies complicated by preeclampsia enables normalization of their gene expression. The affected molecules include SEMA3B, which down-regulates vascular endothelial growth factor signaling through the PI3K/AKT and GSK3 pathways. Thus, some aspects of the aberrant differentiation of cytotrophoblasts within the uterine wall that is observed in situ may be reversible. The next challenge is asking what the instigating causes are. There is added urgency to finding the answers, because these pathways could be valuable therapeutic targets for reversing abnormal placental function in patients.

Understanding and Managing Pregnancy in Patients with Lupus

Systemic lupus erythematosus (SLE) is a chronic, multisystemic autoimmune disease that occurs predominantly in women of fertile age. The association of SLE and pregnancy, mainly with active disease and especially with nephritis, has poorer pregnancy outcomes, with increased frequency of preeclampsia, fetal loss, prematurity, growth restriction, and newborns small for gestational age. Therefore, SLE pregnancies are considered high risk condition, should be monitored frequently during pregnancy and delivery should occur in a controlled setting. Pregnancy induces dramatic immune and neuroendocrine changes in the maternal body in order to protect the fetus from immunologic attack and these modifications can be affected by SLE. The risk of flares depends on the level of maternal disease activity in the 6–12 months before conception and is higher in women with repeated flares before conception, in those who discontinue useful medications and in women with active glomerulonephritis at conception. It is a challenge to differentiate lupus nephritis from preeclampsia and, in this context, the angiogenic and antiangiogenic cytokines are promising. Prenatal care of pregnant patients with SLE requires close collaboration between rheumatologist and obstetrician. Planning pregnancy is essential to increase the probability of successful pregnancies.