Involvement of estrogen-related receptor-γ and mitochondrial content in intrauterine growth restriction and preeclampsia

Variants and Haplotypes of SIRT1 (rs7895833, rs7069102, and rs2273773) are Associated with the Risk of Preeclampsia and Affect the Trace Elements and Antioxidant Enzymes Levels

Preeclampsia is the most common and serious complication of pregnancy. Variants of Sirtuin-1 (SIRT1) as a key player in the regulation of oxidant/antioxidant signaling pathways might be involved in the pathogenesis of preeclampsia. In the present case-control study 300 women with and without preeclampsia were studied for SIRT1 variants (rs7895833, rs7069102, and rs2273773) and haplotypes. Also, the relationship of glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities and Zn, Cu, and Se levels to the polymorphisms were investigated. The SIRT1 rs7895833 A > G, rs7069102 C > G, and the rs2273773 C > T polymorphisms were associated with the risk of preeclampsia. We found the haplotypes G (rs7895833) C (rs7069102) C (rs2273773), GCC, and ACC compared to the AGT decreased the risk of preeclampsia. The risk haplotype of AGT was associated with higher GPx activity compared to the GCC haplotype. A significantly higher level of Cu and lower levels of Zn and Se in patients with preeclampsia compared to controls were detected. Also, a significantly lower SOD and higher GPx activity in preeclamptic patients compared to controls were found. The three risk genotypes of AA (rs7895833), GG (rs7069102), and TT (rs2273773) significantly decreased the Zn level and SOD activity, and the TT genotype (rs2273773) increased the Cu level in all studied women. The presence of rs7069102 polymorphism was associated with enhanced systolic blood pressure. For the first time, we indicated three SIRT1 polymorphisms and the AGT haplotype are risk factors for preeclampsia development. Also, SIRT1 variants and haplotypes affect the levels of antioxidant enzymes and their cofactors, complicating the pregnancy outcome.

Mitochondrial quality control alterations and placenta-related disorders

Mitochondria are ubiquitous in eukaryotic cells. Normal maintenance of function is the premise and basis for various physiological activities. Mitochondrial dysfunction is commonly observed in a wide range of pathological conditions, such as neurodegenerative, metabolic, cardiovascular, and various diseases related to foetal growth and development. The placenta is a highly energy-dependent organ that acts as an intermediary between the mother and foetus and functions to maintain foetal growth and development. Recent studies have demonstrated that mitochondrial dysfunction is associated with placental disorders. Defects in mitochondrial quality control mechanisms may lead to preeclampsia and foetal growth restriction. In this review, we address the quality control mechanisms of mitochondria and the relevant pathologies of mitochondrial dysfunction in placenta-related diseases, such as preeclampsia and foetal growth restriction. This review also investigates the relation between mitochondrial dysfunction and placental disorders.

Expression and significance of silent information regulator two homolog 1 in the placenta and plasma of patients with pre-eclampsia-a meta-analysis

OBJECTIVE

This study aimed to collect, organize, and conduct a meta-analysis of the literature on the expression of silent information regulator two homolog 1 (SIRT1) in the placental tissue and plasma of patients with pre-eclampsia.

METHODS

The enrolled patients were divided into two groups: the pre-eclampsia group and the healthy group. This study summarized and analyzed the demographic characteristics of the two groups, including pregnancy age, gestational weeks, parity, gravidity, blood pressure, Body Mass Index, newborn weight, placental weight, and SIRT1 expression in placental tissue and maternal plasma.

RESULTS

Eleven studies were included in this research, with 586 cases in the pre-eclampsia group and 479 cases in the control group. Three research studies are reporting immunohistochemistry tests, among which the pre-eclampsia group had a positivity rate of 30.24% (62/205), while the control group had 58.02% (76/131); the two groups have a significant difference (p < 0.05). Two research studies reported the results of ELISA tests, with 107 cases in the pre-eclampsia group and 125 cases in the control group. A comparison of the SIRT1 test results showed a statistically significant difference between the two groups (p < 0.05). Pre-eclampsia group patients had lower gestational weeks, newborn birth weight, and placental weight compared to the healthy control group (all p < 0.05). However, systolic and diastolic blood pressures were higher in the pre-eclampsia group than in the control group (p < 0.05).

CONCLUSION

SIRT1 expression is downregulated in pre-eclampsia patients' plasma and placental tissue. Further research is needed to validate this conclusion.

Effects of sirtuin 1 deficiency on trophoblasts and its implications in the pathogenesis of pre-eclampsia

BACKGROUND

Sirtuin 1 (SIRT1) is mainly localised in syncytiotrophoblasts and cytotrophoblasts, and is involved in pregnancy regulation. However, data on the association between SIRT1 and pre-eclampsia (PE) remains limited. This study aimed to investigate the role of SIRT1 in PE pathophysiology.

METHODS

Placental SIRT1 expression, as well as serum SIRT1, placental growth factor (PlGF), and soluble FMS-like tyrosine kinase 1 (sFlt-1) levels, were measured using quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and enzyme-linked immunosorbent assays in 40 healthy pregnant women (NP group) and 40 women with severe PE (PE group). Additionally, the effects of SIRT1 on the migration, invasion, PlGF, and sFlt-1 secretion of HTR-8/SVneo cells were analysed.

RESULTS

SIRT1 expression was significantly reduced in the placenta of patients with severe PE compared with that in healthy pregnant women. Compared with the NP group, serum SIRT1 and PlGF expression was significantly lower in the PE group; however, the expression of serum sFlt-1 was significantly higher in the PE group. Correlation analysis showed that in the PE group, placental SIRT1 protein levels positively correlated with serum PlGF levels (r = 0.468, P = .002) and negatively correlated with serum sFlt-1 levels (r = -0.542, P < .001). Cells with downregulated SIRT1 had a significantly shorter migration distance and a prominently reduced number of invasive cells compared with the corresponding negative control group, suggesting that SIRT1 deficiency may inhibit the migration and invasive ability of HTR-8/SVneo cells. The opposite results were observed after transfection with lentivirus overexpressing SIRT1. Compared with the corresponding controls, cells with downregulated SIRT1 had significantly reduced PlGF levels and significantly increased sFlt-1 levels in the cell culture supernatants, whereas SIRT1 overexpression produced the opposite results.

CONCLUSIONS

SIRT1 deficiency may contribute to the pathogenesis of pre-eclampsia by reducing trophoblastic migration, invasion, and PlGF secretion and increasing sFlt-1 secretion.

Elevated gestational testosterone impacts vascular and uteroplacental function

Maternal vascular adaptations to establish an adequate blood supply to the uterus and placenta are essential for optimal nutrient and oxygen delivery to the developing fetus in eutherian mammals, including humans. Numerous factors contribute to maintaining appropriate hemodynamics and placental vascular development throughout pregnancy. Failure to achieve or sustain these pregnancy-associated changes in women is strongly associated with an increased risk of antenatal complications, such as preeclampsia, a hypertensive disorder of pregnancy. The precise etiology of preeclampsia is unknown, but emerging evidence points to a potential role for androgens. The association between androgens and maternal cardiovascular and placental function merits particular attention due to the notable 2- to 3-fold elevated plasma testosterone (T) levels observed in preeclampsia. T levels in preeclamptic women positively correlate with vascular dysfunction, and preeclampsia is associated with increased androgen receptor (AR) levels in placental tissues. Moreover, animal studies replicating the pattern and magnitude of T increase observed in preeclamptic pregnancies have reproduced key features of preeclampsia, including gestational hypertension, endothelial dysfunction, heightened vasoconstriction to angiotensin II, impaired spiral artery remodeling, placental hypoxia, reduced nutrient transport, and fetal growth restriction. Collectively, these findings suggest that AR-mediated activity plays a significant role in the clinical presentation of preeclampsia. This review critically evaluates this hypothesis, considering both clinical and preclinical evidence.

Rational Design of Nanomedicine for Placental Disorders: Birthing a New Era in Women's Reproductive Health

The placenta is a transient organ that forms during pregnancy and acts as a biological barrier, mediating exchange between maternal and fetal circulation. Placental disorders, such as preeclampsia, fetal growth restriction, placenta accreta spectrum, and gestational trophoblastic disease, originate in dysfunctional placental development during pregnancy and can lead to severe complications for both the mother and fetus. Unfortunately, treatment options for these disorders are severely lacking. Challenges in designing therapeutics for use during pregnancy involve selectively delivering payloads to the placenta while protecting the fetus from potential toxic side effects. Nanomedicine holds great promise in overcoming these barriers; the versatile and modular nature of nanocarriers, including prolonged circulation times, intracellular delivery, and organ-specific targeting, can control how therapeutics interact with the placenta. In this review, nanomedicine strategies are discussed to treat and diagnose placental disorders with an emphasis on understanding the unique pathophysiology behind each of these diseases. Finally, prior study of the pathophysiologic mechanisms underlying these placental disorders has revealed novel disease targets. These targets are highlighted here to motivate the rational design of precision nanocarriers to improve therapeutic options for placental disorders.

Comparison of Placental HSD17B1 Expression and Its Regulation in Various Mammalian Species

During mammalian gestation, large amounts of progesterone are produced by the placenta and circulate for the maintenance of pregnancy. In contrast, primary plasma estrogens are different between species. To account for this difference, we compared the expression of ovarian and placental steroidogenic genes in various mammalian species (mouse, guinea pig, porcine, ovine, bovine, and human). Consistent with the ability to synthesize progesterone, CYP11A1/Cyp11a1, and bi-functional HSD3B/Hsd3b genes were expressed in all species. CYP17A1/Cyp17a1 was expressed in the placenta of all species, excluding humans. CYP19A/Cyp19a1 was expressed in all placental estrogen-producing species, whereas estradiol-producing HSD17B1 was only strongly expressed in the human placenta. The promoter region of HSD17B1 in various species possesses a well-conserved SP1 site that was activated in human placental cell line JEG-3 cells. However, DNA methylation analyses in the ovine placenta showed that the SP1-site in the promoter region of HSD17B1 was completely methylated. These results indicate that epigenetic regulation of HSD17B1 expression is important for species-specific placental sex steroid production. Because human HSD17B1 showed strong activity for the conversion of androstenedione into testosterone, similar to HSD17B1/Hsd17b1 in other species, we also discuss the biological significance of human placental HSD17B1 based on the symptoms of aromatase-deficient patients.

Maternal-fetal genetic interactions, imprinting, and risk of placental abruption

RESULTS

Abruption cases were more likely to experience preeclampsia, have shorter gestational age, and deliver infants with lower birthweight compared with controls. Models with MFGI effects provided improved fit than models with only maternal and fetal genotype main effects for SNP rs12530904 (p-value = 1.2e-04) in calcium/calmodulin-dependent protein kinase [CaM kinase] II beta (CAMK2B), and, SNP rs73136795 (p-value = 1.9e-04) in peroxisome proliferator-activated receptor-gamma (PPARG), both MB genes. We identified 320 SNPs in 45 maternally-imprinted genes (including potassium voltage-gated channel subfamily Q member 1 [KCNQ1], neurotrimin [NTM], and, ATPase phospholipid transporting 10 A [ATP10A]) associated with abruption. Top hits included rs2012323 (p-value = 1.6E-16) and rs12221520 (p-value1.3e-13) in KCNQ1, rs8036892 (p-value = 9.3E-17) and rs188497582 in ATP10A, rs12589854 (p-value = 2.9E-11) and rs80203467 (p-value = 4.6e-11) in maternally expressed 8, small nucleolar RNA host (MEG8), and rs138281088 in solute carrier family 22 member 2 (SLC22A2) (p-value = 6.8e-9).

CONCLUSIONS

We identified novel PA-related maternal-fetal MB gene interactions and imprinting effects that highlight the role of the fetus in PA risk development. Findings can inform mechanistic investigations to understand the pathogenesis of PA.

Mitochondria Targeted Antioxidant Significantly Alleviates Preeclampsia Caused by 11β-HSD2 Dysfunction via OPA1 and MtDNA Maintenance

We have previously demonstrated that placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) dysfunction contributes to PE pathogenesis. We sought to elucidate molecular mechanisms underlying 11β-HSD2 dysfunction-induced PE and to seek potential therapeutic targets using a 11β-HSD2 dysfunction-induced PE-like rat model as well as cultured extravillous trophoblasts (EVTs) since PE begins with impaired function of EVTs. In 11β-HSD2 dysfunction-induced PE-like rat model, we revealed that placental mitochondrial dysfunction occurred, which was associated with mitDNA instability and impaired mitochondrial dynamics, such as decreased optic atrophy 1 (OPA1) expression. MitoTEMPO treatment significantly alleviated the hallmark of PE-like features and improved mitDNA stability and mitochondrial dynamics in the placentas of rat PE-like model. In cultured human EVTs, we found that 11β-HSD2 dysfunction led to mitochondrial dysfunction and disrupted mtDNA stability. MitoTEMPO treatment improved impaired invasion and migration induced by 11β-HSD2 dysfunction in cultured EVTs. Further, we revealed that OPA1 was one of the key factors that mediated 11β-HSD2 dysfunction-induced excess ROS production, mitochondrial dysfunction and mtDNA reduction. Our data indicates that 11β-HSD2 dysfunction causes mitochondrial dysfunctions, which impairs trophoblast function and subsequently results in PE development. Our study immediately highlights that excess ROS is a potential therapeutic target for PE.

Placental expression of Estrogen related receptor gamma (ESRRG) is reduced in FGR pregnancies and is mediated by hypoxia

Fetal growth restriction (FGR) describes a fetus which has not achieved its genetic growth potential; it is closely linked to placental dysfunction and uteroplacental hypoxia. Estrogen-related receptor gamma (ESRRG) is regulated by hypoxia and is highly expressed in the placenta. We hypothesized ESRRG is a regulator of hypoxia-mediated placental dysfunction in FGR pregnancies. Placentas were collected from women delivering appropriate for gestational age (AGA; n = 14) or FGR (n = 14) infants. Placental explants (n = 15) from uncomplicated pregnancies were cultured for up to 4 days in 21% or 1% O₂, or with 200 μM cobalt chloride (CoCl₂), or treated with the ESRRG agonists DY131 under different oxygen concentrations. RT-PCR, Western blotting, and immunochemistry were used to assess mRNA and protein levels of ESRRG and its localization in placental tissue from FGR or AGA pregnancies, and in cultured placental explants. ESRRG mRNA and protein expression were significantly reduced in FGR placentas, as was mRNA expression of the downstream targets of ESRRG, hydroxysteroid 11-beta dehydrogenase 2 (HSD11B2), and cytochrome P-450 (CYP19A1.1). Hypoxia-inducible factor 1-alpha protein localized to the nuclei of the cytotrophoblasts and stromal cells in the explants exposed to CoCl₂ or 1% O₂. Both hypoxia and CoCl₂ treatment decreased ESRRG and its downstream genes’ mRNA expression, but not ESRRG protein expression. DY131 increased the expression of ESRRG signaling pathways and prevented abnormal cell turnover induced by hypoxia. These data show that placental ESRRG is hypoxia-sensitive and altered ESRRG-mediated signaling may contribute to hypoxia-induced placental dysfunction in FGR. Furthermore, DY131 could be used as a novel therapeutic approach for the treatment of placental dysfunction.

Current Studies of Mitochondrial Quality Control in the Preeclampsia

Mitochondria are cellular energy powerhouses that play important roles in regulating cellular processes. Mitochondrial quality control (mQC), including mitochondrial biogenesis, mitophagy, mitochondrial fusion and fission, maintains physiological demand and adapts to changed conditions. mQC has been widely investigated in neurodegeneration, cardiovascular disease and cancer because of the high demand for ATP in these diseases. Although placental implantation and fetal growth similarly require a large amount of energy, the investigation of mQC in placental-originated preeclampsia (PE) is limited. We elucidate mitochondrial morphology and function in different pregnancy stages, outline the role of mQC in cellular homeostasis and PE and summarize the current findings of mQC-related PE studies. This review also provides suggestions on the future investigation of mQC in PE, which will lead to the development of new prevention and therapy strategies for PE.

Sex-specific effects of Bisphenol a on the signalling pathway of ESRRG in the human placenta

Bisphenol A (BPA) exposure during pregnancy is associated with low fetal weight, particularly in male fetuses. The expression of estrogen-related receptor gamma (ESRRG), a receptor for BPA in the human placenta, is reduced in fetal growth restriction. This study sought to explore whether ESRRG signaling mediates BPA-induced placental dysfunction and determine whether changes in the ESRRG signaling pathway are sex-specific. Placental villous explants from 18 normal term pregnancies were cultured with a range of BPA concentrations (1 nM–1 μM). Baseline BPA concentrations in the placental tissue used for explant culture ranged from 0.04 to 5.1 nM (average 2.3 ±1.9 nM; n = 6). Expression of ESRRG signaling pathway constituents and cell turnover were quantified. BPA (1 μM) increased ESRRG mRNA expression after 24 h in both sexes. ESRRG mRNA and protein expression was increased in female placentas treated with 1 μM BPA for 24 h but was decreased in male placentas treated with 1 nM or 1 μM for 48 h. Levels of 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) and placenta specific-1 (PLAC1), genes downstream of ESRRG, were also affected. HSD17B1 mRNA expression was increased in female placentas by 1 μM BPA; however, 1 nM BPA reduced HSD17B1 and PLAC1 expression in male placentas at 48 h. BPA treatment did not affect rates of proliferation, apoptosis, or syncytiotrophoblast differentiation in cultured villous explants. This study has demonstrated that BPA affects the ESRRG signaling pathway in a sex-specific manner in human placentas and a possible biological mechanism to explain the differential effects of BPA exposure on male and female fetuses observed in epidemiological studies.

Hypoxic effects on the mitochondrial content and functions of the placenta in fetal growth restriction

INTRODUCTION

In this study we examined the hypothesis that a hypoxic intrauterine environment causes mitochondrial dysfunction of trophoblasts in fetal growth restriction (FGR).

METHODS

The mtDNA content, mRNA levels of mitochondrial encoded genes (ND6, COX I), mitochondrial membrane proteins (COX I, COX IV and VDAC), HIF-1α and BINP3 (mitophagy receptor) protein levels were examined in FGR placentas and normal placentas. The mitochondrial function (ATP production and mitochondrial membrane potential-ΔΨm) and above related proteins were further examined in hypoxic HTR-8/SVneo cells induced by cobalt chloride (CoCl2). Mitophagy and its regulating mechanism under hypoxia in FGR was also investigated.

RESULTS

Compared with normal controls, both FGR placentas and CoCl2-treated trophoblast cells demonstrated statistically lower mtDNA content, reduced mRNAs of mitochondrial encoding genes, and decreased mitochondrial membrane proteins, accompanied by increased HIF-1α. Mitochondrial functions were impaired as demonstrated by decreased ATP production, and, reduced ΔΨm in CoCl2-treated cells. Meanwhile, mitophagy was markedly enhanced as indicated by increased LC3 fluorescent puncta in mitochondria of hypoxic trophoblastic cells. The upregulated BINP3 expression was demonstrated in FGR placentas as well as in hypoxic trophoblastic cells.

DISCUSSION

We demonstrated that hypoxic conditions lead to impaired mitochondrial function in trophoblasts in FGR. Reduced mtDNA may be associated with enhanced mitophagy via activating HIF-1α/BINP3 signalling pathway, that may, in turn, affect nutrition and energy transfer to the growth-restricted fetus.

Placental mitochondrial function as a driver of angiogenesis and placental dysfunction

The placenta is a highly vascularized and complex foetal organ that performs various tasks, crucial to a healthy pregnancy. Its dysfunction leads to complications such as stillbirth, preeclampsia, and intrauterine growth restriction. The specific cause of placental dysfunction remains unknown. Recently, the role of mitochondrial function and mitochondrial adaptations in the context of angiogenesis and placental dysfunction is getting more attention. The required energy for placental remodelling, nutrient transport, hormone synthesis, and the reactive oxygen species leads to oxidative stress, stemming from mitochondria. Mitochondria adapt to environmental changes and have been shown to adjust their oxygen and nutrient use to best support placental angiogenesis and foetal development. Angiogenesis is the process by which blood vessels form and is essential for the delivery of nutrients to the body. This process is regulated by different factors, pro-angiogenic factors and anti-angiogenic factors, such as sFlt-1. Increased circulating sFlt-1 levels have been linked to different preeclamptic phenotypes. One of many effects of increased sFlt-1 levels, is the dysregulation of mitochondrial function. This review covers mitochondrial adaptations during placentation, the importance of the anti-angiogenic factor sFlt-1in placental dysfunction and its role in the dysregulation of mitochondrial function.

Protective role of SIRT1-mediated Sonic Hedgehog signaling pathway in the preeclampsia rat models

OBJECTIVE

To explore the role of silent information regulator 1 (SIRT1)-mediated Sonic Hedgehog (SHH) pathway in reduced uterine perfusion pressure (RUPP) model of preeclampsia (PE) in rats.

METHODS

The pregnant rats were divided into sham, RUPP, RUPP + rSIRT1 (recombinant SIRT1 protein), RUPP + rSHH (recombinant SHH protein), and RUPP + rSIRT1+ Cy (cyclopamine, an SHH pathway inhibitor) groups, followed by the determination of mean arterial pressure (MAP) and pregnancy outcome. The gene or protein expression was determined by enzyme-linked immunosorbent assay (ELISA), quantitative reverse transcription-polymerase chain reaction (qRT-PCR), or Western blotting.

RESULTS

RUPP rats showed increases MAP with the lower levels of vascular endothelial growth factor (VEGF) and nitrite and nitrate (NOx), as well as the higher levels of soluble FMS-like tyrosine kinase-1 (sFlt-1), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in maternal plasma, which was attenuated after rSIRT1 or rSHH treatment. Besides, the improvement in the pregnancy outcome was seen in the rats from the RUPP + rSIRT1/rSHH groups as compared with the RUPP group. However, the therapeutic effect of rSIRT1 was reversed by cyclopamine. Placenta tissues of RUPP rats manifested the down-regulations of SIRT1, Patched-1 (PTCH1), and GLI family zinc finger 2 (GLI2), which were up-regulated in the RUPP + rSIRT1 group.

CONCLUSION

SIRT1 was down-regulated while SHH pathway was inhibited in the placental tissue of PE rats. SIRT1 improved the blood pressure, angiogenic imbalance, inflammation, and pregnancy outcome in PE rats via SHH pathway, supporting its potential use for the treatment of PE.

Placental mitochondrial DNA mutational load and perinatal outcomes: Findings from a multi-ethnic pregnancy cohort

Mitochondria fuel placental activity, with mitochondrial dysfunction implicated in several perinatal complications. We investigated placental mtDNA mutational load using NextGen sequencing in relation to birthweight and gestational length among 358 mother-newborn pairs. We found that higher heteroplasmy, especially in the hypervariable displacement loop region, was associated with shorter gestational length. Results were similar among male and female pregnancies, but stronger in magnitude among females. With regard to growth, we observed that higher mutational load was associated with lower birthweight-for-gestational age (BWGA) among females, but higher BWGA among males. These findings support potential sex-differential fetal biological strategies for coping with increased heteroplasmies.

Placental Mitochondrial Abnormalities in Preeclampsia

Preeclampsia complicates 5–8% of all pregnancies worldwide, and although its pathophysiology remains obscure, placental oxidative stress and mitochondrial abnormalities are considered to play a key role. Mitochondrial abnormalities in preeclamptic placentae have been described, but the extent to which mitochondrial content and the molecular pathways controlling this (mitochondrial biogenesis and mitophagy) are affected in preeclamptic placentae is unknown. Therefore, in preeclamptic (n = 12) and control (n = 11) placentae, we comprehensively assessed multiple indices of placental antioxidant status, mitochondrial content, mitochondrial biogenesis, mitophagy, and mitochondrial fusion and fission. In addition, we also explored gene expression profiles related to inflammation and apoptosis. Preeclamptic placentae were characterized by higher levels of oxidized glutathione, a higher total antioxidant capacity, and higher mRNA levels of the mitochondrial-located antioxidant enzyme manganese-dependent superoxide dismutase 2 compared to controls. Furthermore, mitochondrial content was significantly lower in preeclamptic placentae, which was accompanied by an increased abundance of key constituents of glycolysis. Moreover, mRNA and protein levels of key molecules involved in the regulation of mitochondrial biogenesis were lower in preeclamptic placentae, while the abundance of constituents of the mitophagy, autophagy, and mitochondrial fission machinery was higher compared to controls. In addition, we found evidence for activation of apoptosis and inflammation in preeclamptic placentae. This study is the first to comprehensively demonstrate abnormalities at the level of the mitochondrion and the molecular pathways controlling mitochondrial content/function in preeclamptic placentae. These aberrations may well contribute to the pathophysiology of preeclampsia by upregulating placental inflammation, oxidative stress, and apoptosis.

Serum kallistatin level is decreased in women with preeclampsia

OBJECTIVES

To evaluate the serum levels of the serine proteinase inhibitor kallistatin in women with preeclampsia (PE).

METHODS

The clinical and laboratory parameters of 55 consecutive women with early-onset PE (EOPE) and 55 consecutive women with late-onset PE (LOPE) were compared with 110 consecutive gestational age (GA)-matched (±1 week) pregnant women with an uncomplicated pregnancy and an appropriate for gestational age fetus.

RESULTS

Mean serum kallistatin was significantly lower in women with PE compared to the GA-matched-controls (27.74±8.29 ng/mL vs. 37.86±20.64 ng/mL, p<0.001); in women with EOPE compared to that of women in the control group GA-matched for EOPE (24.85±6.65 ng/mL vs. 33.37±17.46 ng/mL, p=0.002); and in women with LOPE compared to that of women in the control group GA-matched for LOPE (30.87±8.81 ng/mL vs. 42.25±22.67 ng/mL, p=0.002). Mean serum kallistatin was significantly lower in women with EOPE compared to LOPE (24.85±6.65 ng/mL vs. 30.87±8.81 ng/mL, p<0.001). Serum kallistatin had negative correlations with systolic and diastolic blood pressure, creatinine, and positive correlation with GA at sampling and GA at birth.

CONCLUSIONS

Serum kallistatin levels are decreased in preeclamptic pregnancies compared to the GA-matched-controls. This decrease was also significant in women with EOPE compared to LOPE. Serum kallistatin had negative correlation with systolic and diastolic blood pressure, creatinine and positive correlation with GA at sampling and GA at birth.

Testosterone Decreases Placental Mitochondrial Content and Cellular Bioenergetics

Placental mitochondrial dysfunction plays a central role in the pathogenesis of preeclampsia. Since preeclampsia is a hyperandrogenic state, we hypothesized that elevated maternal testosterone levels induce damage to placental mitochondria and decrease bioenergetic profiles. To test this hypothesis, pregnant Sprague–Dawley rats were injected with vehicle or testosterone propionate (0.5 mg/kg/day) from gestation day (GD) 15 to 19. On GD20, the placentas were isolated to assess mitochondrial structure, copy number, ATP/ADP ratio, and biogenesis (Pgc-1α and Nrf1). In addition, in vitro cultures of human trophoblasts (HTR-8/SVneo) were treated with dihydrotestosterone (0.3, 1.0, and 3.0 nM), and bioenergetic profiles using seahorse analyzer were assessed. Testosterone exposure in pregnant rats led to a 2-fold increase in plasma testosterone levels with an associated decrease in placental and fetal weights compared with controls. Elevated maternal testosterone levels induced structural damage to the placental mitochondria and decreased mitochondrial copy number. The ATP/ADP ratio was reduced with a parallel decrease in the mRNA and protein expression of Pgc-1α and Nrf1 in the placenta of testosterone-treated rats compared with controls. In cultured trophoblasts, dihydrotestosterone decreased the mitochondrial copy number and reduced PGC-1α, NRF1 mRNA, and protein levels without altering the expression of mitochondrial fission/fusion genes. Dihydrotestosterone exposure induced significant mitochondrial energy deficits with a dose-dependent decrease in basal respiration, ATP-linked respiration, maximal respiration, and spare respiratory capacity. In summary, our study suggests that the placental mitochondrial dysfunction induced by elevated maternal testosterone might be a potential mechanism linking preeclampsia to feto-placental growth restriction.

Analysis of SIRT1 Expression in Plasma and in an In Vitro Model of Preeclampsia

Preeclampsia (PE) is a pregnancy-specific disorder that affects 3–8% expecting mothers worldwide being one of the main causes of maternal and fetal morbidity and mortality. The search for altered circulating molecules in PE is an important target to better understand the pathophysiology of this disease. Therefore, we evaluated Sirtuin-1 (SIRT1) concentration in plasma from healthy pregnant (HP) women, gestational hypertensive women (GH), and preeclampsia women (PE) via enzyme-linked immunosorbent assay (ELISA). We also measured intracellular SIRT1 in HUVECs incubated with plasma from PE patients compared to HP and GH via Western Blot Assay. Statistical differences were considered when p < 0.05. SIRT1 was downregulated in PE compared to HP and GH, both in plasma and in in vitro assay. Similarly, SIRT1 was also reduced in pregnant women who subsequently developed PE (case) compared to women who had healthy pregnancies (control). This reduction may be indicative of possible underlying pathophysiology mechanisms in PE.

Reactive oxygen species from mitochondria impacts trophoblast fusion and the production of endocrine hormones by syncytiotrophoblasts

The placenta, a tissue that is metabolically active and rich in mitochondria, forms a critical interface between the mother and developing fetus. Oxidative stress within this tissue, derived from the dysregulation of reactive oxygen species (ROS), has been linked to a number of adverse fetal outcomes. While such outcomes have been associated with mitochondrial dysfunction, the causal role of mitochondrial dysfunction and mitochondrially generated ROS in altering the process of placentation remains unclear. In this study, mitochondrial complex I activity was attenuated using 10 nM rotenone to induce cellular oxidative stress by increasing mitochondrial ROS production in the BeWo choriocarcinoma cell line. Increased mitochondrial ROS resulted in a significant decrease in the transcripts which encode for proteins associated with fusion (GCM1, ERVW-1, and ERVFRD-1) resulting in a 5-fold decrease in the percentage of BeWo fusion. This outcome was associated with increased indicators of mitochondrial fragmentation, as determined by decreased expression of MFN2 and OPA1 along with an increase in a marker of mitochondrial fission (DRP1). Importantly, increased mitochondrial ROS also resulted in a 5.0-fold reduction of human placental lactogen (PL) and a 4.4-fold reduction of insulin like growth factor 2 (IGF2) transcripts; hormones which play an important role in regulating fetal growth. The pre-treatment of rotenone-exposed cells with 5 mM N-acetyl cysteine (NAC) resulted in the prevention of these ROS mediated changes in BeWo function and supports a central role for mitochondrial ROS signaling in the maintenance and function of the materno-fetal interface.

Impaired Mitochondrial Function Results from Oxidative Stress in the Full-Term Placenta of Sows with Excessive Back-Fat

The aim of this study was to determine the effect of excessive back-fat (BF) of sows on placental oxidative stress, ATP generation, mitochondrial alterations in content and structure, and mitochondrial function in isolated trophoblasts. Placental tissue was collected by vaginal delivery from BFI (15-20 mm, n = 10) and BFII (21-27 mm, n = 10) sows formed according to BF at mating. Our results demonstrated that excessive back-fat contributed to augmented oxidative stress in term placenta, as evidenced by excessive production of ROS, elevated protein carbonylation, and reduced SOD, GSH-PX, and CAT activities (p < 0.05). Indicative of mitochondrial dysfunction, reduced mitochondrial respiration in cultured trophoblasts was linked to decreased ATP generation, lower mitochondrial Complex I activity and reduced expression of electron transport chain subunits in placenta of BFII sows (p < 0.05). Meanwhile, we observed negative alterations in mitochondrial biogenesis and structure in the placenta from BFII group (p < 0.05). Finally, our in vitro studies showed lipid-induced ROS production resulted in mitochondrial alterations in trophoblasts, and these effects were blocked by antioxidant treatment. Together, these data reveal that excessive back-fat aggravates mitochondrial injury induced by increased oxidative stress in pig term placenta, which may have detrimental consequences on placental function and therefore impaired fetal growth and development.

Complex, coordinated and highly regulated changes in placental signaling and nutrient transport capacity in IUGR

The most common cause of intrauterine growth restriction (IUGR) in the developed world is placental insufficiency, a concept often used synonymously with reduced utero-placental and umbilical blood flows. However, placental insufficiency and IUGR are associated with complex, coordinated and highly regulated changes in placental signaling and nutrient transport including inhibition of insulin and mTOR signaling and down-regulation of specific amino acid transporters, Na+/K+-ATPase, the Na+/H+-exchanger, folate and lactate transporters. In contrast, placental glucose transport capacity is unaltered and Ca2+-ATPase activity and the expression of proteins involved in placental lipid transport are increased in IUGR. These findings are not entirely consistent with the traditional view that the placenta is dysfunctional in IUGR, but rather suggest that the placenta adapts to reduce fetal growth in response to an inability of the mother to allocate resources to the fetus. This new model has implications for the understanding of the mechanisms underpinning IUGR and for the development of intervention strategies.

Single-cell RNA sequencing reveals regulatory mechanism for trophoblast cell-fate divergence in human peri-implantation conceptuses

Multipotent trophoblasts undergo dynamic morphological movement and cellular differentiation after conceptus implantation to generate placenta. However, the mechanism controlling trophoblast development and differentiation during peri-implantation development in human remains elusive. In this study, we modeled human conceptus peri-implantation development from blastocyst to early postimplantation stages by using an in vitro coculture system and profiled the transcriptome of 476 individual trophoblast cells from these conceptuses. We revealed the genetic networks regulating peri-implantation trophoblast development. While determining when trophoblast differentiation happens, our bioinformatic analysis identified T-box transcription factor 3 (TBX3) as a key regulator for the differentiation of cytotrophoblast (CT) into syncytiotrophoblast (ST). The function of TBX3 in trophoblast differentiation is then validated by a loss-of-function experiment. In conclusion, our results provided a valuable resource to study the regulation of trophoblasts development and differentiation during human peri-implantation development.

The trichloroethylene metabolite S-(1,2-dichlorovinyl)-L-cysteine induces progressive mitochondrial dysfunction in HTR-8/SVneo trophoblasts

Trichloroethylene is an industrial solvent and common environmental pollutant. Despite efforts to ban trichloroethylene, its availability and usage persist globally, constituting a hazard to human health. Recent studies reported associations between maternal trichloroethylene exposure and increased risk for low birth weight. Despite these associations, the toxicological mechanism underlying trichloroethylene adverse effects on pregnancy remains largely unknown. The trichloroethylene metabolite S-(1,2-dichlorovinyl)-L-cysteine (DCVC) induces mitochondrial-mediated apoptosis in a trophoblast cell line. To gain further understanding of mitochondrial-mediated DCVC placental toxicity, this study investigated the effects of DCVC exposure on mitochondrial function using non-cytolethal concentrations in placental cells. Human trophoblasts, HTR-8/SVneo, were exposed in vitro to a maximum of 20 μM DCVC for up to 12 h. Cell-based oxygen consumption and extracellular acidification assays were used to evaluate key aspects of mitochondrial function. Following 6 h of exposure to 20 μM DCVC, elevated oxygen consumption, mitochondrial proton leak and sustained energy coupling deficiency were observed. Similarly, 12 h of exposure to 20 μM DCVC decreased mitochondrial-dependent basal, ATP-linked and maximum oxygen consumption rates. Using the fluorochrome TMRE, dissipation of mitochondrial membrane potential was detected after a 12-h exposure to 20 μM DCVC, and (±)-α-tocopherol, a known suppressor of lipid peroxidation, attenuated DCVC-stimulated mitochondrial membrane depolarization but failed to rescue oxygen consumption perturbations. Together, these results suggest that DCVC caused progressive mitochondrial dysfunction, resulting in lipid peroxidation-associated mitochondrial membrane depolarization. Our findings contribute to the biological plausibility of DCVC-induced placental impairment and provide new insights into the role of the mitochondria in DCVC-induced toxicity.

Δ9-Tetrahydrocannabinol leads to endoplasmic reticulum stress and mitochondrial dysfunction in human BeWo trophoblasts

While studies have demonstrated that the main psychoactive component of cannabis, Δ9-tetrahydrocannabinol (Δ9-THC) alone induces placental insufficiency and fetal growth restriction, the underlying mechanisms remain elusive. Given that both (i) endoplasmic reticulum (ER) stress in pregnancy and (ii) gestational exposure to Δ9-THC leads to placental deficiency, we hypothesized that Δ9-THC may directly induce placental ER stress, influencing trophoblast gene expression and mitochondrial function. BeWo human trophoblast cells treated with Δ9-THC (3-30 μM) led to a dose-dependent increase in all ER stress markers and CHOP; these effects could be blocked with CB1R/CB2R antagonists. Moreover, expression of ER stress-sensitive genes ERRγ, VEGFA, and FLT-1 were increased by Δ9-THC, and abrogated with the ER stress inhibitor TUDCA. Δ9-THC also diminished mitochondrial respiration and ATP-coupling due to decreased abundance of mitochondrial chain complex proteins. Collectively, these findings indicate that Δ9-THC can directly augment ER stress resulting in aberrant placental gene expression and impaired mitochondrial function.

Mitochondrial implications in human pregnancies with intrauterine growth restriction and associated cardiac remodelling

Intrauterine growth restriction (IUGR) is an obstetric complication characterised by placental insufficiency and secondary cardiovascular remodelling that can lead to cardiomyopathy in adulthood. Despite its aetiology and potential therapeutics are poorly understood, bioenergetic deficits have been demonstrated in adverse foetal and cardiac development. We aimed to evaluate the role of mitochondria in human pregnancies with IUGR. In a single‐site, cross‐sectional and observational study, we included placenta and maternal peripheral and neonatal cord blood mononuclear cells (PBMC and CBMC) from 14 IUGR and 22 control pregnancies. The following mitochondrial measurements were assessed: enzymatic activities of mitochondrial respiratory chain (MRC) complexes I, II, IV, I + III and II + III, oxygen consumption (cell and complex I‐stimulated respiration), mitochondrial content (citrate synthase [CS] activity and mitochondrial DNA copy number), total ATP levels and lipid peroxidation. Sirtuin3 expression was evaluated as a potential regulator of bioenergetic imbalance. Intrauterine growth restriction placental tissue showed a significant decrease of MRC CI enzymatic activity (P < 0.05) and CI‐stimulated oxygen consumption (P < 0.05) accompanied by a significant increase of Sirtuin3/β‐actin protein levels (P < 0.05). Maternal PBMC and neonatal CBMC from IUGR patients presented a not significant decrease in oxygen consumption (cell and CI‐stimulated respiration) and MRC enzymatic activities (CII and CIV). Moreover, CS activity was significantly reduced in IUGR new‐borns (P < 0.05). Total ATP levels and lipid peroxidation were preserved in all the studied tissues. Altered mitochondrial function of IUGR is especially present at placental and neonatal level, conveying potential targets to modulate obstetric outcome through dietary interventions aimed to regulate Sirtuin3 function.

Mechanistic Target of Rapamycin Complex 1 Promotes the Expression of Genes Encoding Electron Transport Chain Proteins and Stimulates Oxidative Phosphorylation in Primary Human Trophoblast Cells by Regulating Mitochondrial Biogenesis

Trophoblast oxidative phosphorylation provides energy for active transport and protein synthesis, which are critical placental functions influencing fetal growth and long-term health. The molecular mechanisms regulating trophoblast mitochondrial oxidative phosphorylation are largely unknown. We hypothesized that mechanistic Target of Rapamycin Complex 1 (mTORC1) is a positive regulator of key genes encoding Electron Transport Chain (ETC) proteins and stimulates oxidative phosphorylation in trophoblast and that ETC protein expression is down-regulated in placentas of infants with intrauterine growth restriction (IUGR). We silenced raptor (mTORC1 inhibition), rictor (mTORC2 inhibition) or DEPTOR (mTORC1/2 activation) in cultured term primary human trophoblast (PHT) cells. mTORC1 inhibition caused a coordinated down-regulation of 18 genes encoding ETC proteins representing all ETC complexes. Inhibition of mTORC1, but not mTORC2, decreased protein expression of ETC complexes I–IV, mitochondrial basal, ATP coupled and maximal respiration, reserve capacity and proton leak, whereas activation of mTORC1 had the opposite effects. Moreover, placental protein expression of ETC complexes was decreased and positively correlated to mTOR signaling activity in IUGR. By controlling trophoblast ATP production, mTORC1 links nutrient and O₂ availability and growth factor signaling to placental function and fetal growth. Reduced placental mTOR activity may impair mitochondrial respiration and contribute to placental insufficiency in IUGR pregnancies.

Abruptio placentae risk and genetic variations in mitochondrial biogenesis and oxidative phosphorylation: replication of a candidate gene association study

BACKGROUND

Abruptio placentae is a complex multifactorial disease that is associated with maternal and neonatal death and morbidity. Abruptio placentae's high recurrence rate, high prevalence of heritable thrombophilia among women with abruptio placentae, and aggregation of cases in families of women with the disease support the possibility of a genetic predisposition. Previous genome-wide and candidate gene association studies have identified single nucleotide polymorphisms in mitochondrial biogenesis and oxidative phosphorylation genes that potentially are associated with abruptio placentae risk. Perturbations in mitochondrial biogenesis and oxidative phosphorylation, which results in mitochondrial dysfunction, can lead to the impairment of differentiation and invasion of the trophoblast and to several obstetrics complications that include abruptio placentae.

OBJECTIVE

The purpose of this study was to determine whether the results of a candidate genetic association study that indicated a link between DNA variants (implicated in mitochondrial biogenesis and oxidative phosphorylation) and abruptio placentae could be replicated.

STUDY DESIGN

The study was conducted among participants (507 abruptio placentae cases and 1090 control subjects) of the Placental Abruption Genetic Epidemiology study. Weighted genetic risk scores were calculated with the use of abruptio placentae risk-increasing alleles of 11 single nucleotide polymorphisms in 9 mitochondrial biogenesis and oxidative phosphorylation genes (CAMK2B, NR1H3, PPARG, PRKCA, THRB, COX5A, NDUFA10, NDUFA12, and NDUFC2), which previously was reported in the Peruvian Abruptio Placentae Epidemiology study, a study with similar design and study population to the Placental Abruption Genetic Epidemiology study. Logistic regression models were fit to examine associations of weighted genetic risk scores (quartile 1, <25th percentile; quartile 2, 25-50th percentile; quartile 3, 50-70th percentile, and quartile 4, >75th percentile) with risk of abruptio placentae, adjusted for population admixture (the first 4 principal components), maternal age, infant sex, and preeclampsia. The weighted genetic risk score was also modeled as a continuous predictor. To assess potential effect modification, analyses were repeated among strata that were defined by preeclampsia status, maternal age (≥35 vs 18-34 years), and infant sex.

RESULTS

Abruptio placentae cases were more likely to have preeclampsia, shorter gestational age, and lower infant birthweight. Participants in quartile 2 (score, 12.6-13.8), quartile 3 (score, 13.9-15.0) and quartile 4 (score, ≥15.1) had a genetic risk score of 1.45-fold (95% confidence interval, 1.04-2.02; P=.03), a 1.42-fold (95% confidence interval, 1.02-1.98; P=.04), and a 1.75-fold (95% confidence interval, 1.27-2.42; P=7.0E-04) higher odds of abruptio placentae, respectively, compared with those in quartile 1 (score,<12.6; P-for trend=.0003). The risk of abruptio placentae was 1.12-fold (95% confidence interval, 1.05-1.19; P=3.0×1004) higher per 1-unit increase in the score. Among women with preeclampsia, those in quartile 4 had a 3.92-fold (95% confidence interval, 1.48-10.36; P=.01) higher odds of abruptio placentae compared with women in quartile 1. Among normotensive women, women in quartile 4 had a 1.57-fold (95% confidence interval, 1.11-2.21; P=.01) higher odds of abruptio placentae compared with those in quartile 1 (P-for interaction=.12). We did not observe differences in associations among strata defined by maternal age or infant sex.

CONCLUSION

In this study, we replicated previous findings and provide strong evidence for DNA variants that encode for genes that are involved in mitochondrial biogenesis and oxidative phosphorylation pathways, which confers risk for abruptio placentae. These results shed light on the mechanisms that implicate DNA variants that encode for proteins in mitochondrial function that are responsible for abruptio placentae risk. Therapeutic efforts to reduce risk of abruptio placentae can be enhanced by improved biologic understanding of maternal mitochondrial biogenesis/oxidative phosphorylation pathways and identification of women who would be at high risk for abruptio placentae.

Maternal serum mitochondrial DNA (mtDNA) levels are elevated in preeclampsia - A matched case-control study

OBJECTIVE

Oxidative stress and mitochondrial dysfunction may play a crucial role in preeclampsia (PE). The aim of this study was to investigate differences in maternal levels of serum-mitochondrial (mt) DNA, a proposed biomarker for mitochondrial dysfunction, in women with PE compared to healthy pregnant women.

STUDY DESIGN

Using samples obtained from the prospective Biobank study, we measured serum-mtDNA levels in pregnant women diagnosed with PE and in women with uneventful pregnancies, matched for gestational and maternal age, BMI, and smoking status. In a second step, we performed a generalized linear model to detect associations between mtDNA-serum-levels and certain conditions during pregnancy.

RESULTS

Mean mtDNA levels were significantly higher in PE (n = 20) than in matched controls (n = 20) and were 0.00767 (SD 0.00255) U/L and 0.00513 (SD 0.00458) U/L, respectively (p = 0.038). We did not find a significant correlation between higher mtDNA levels and early onset PE, IUGR, maternal age, or maternal BMI. Interestingly, increased mtDNA levels were significantly associated with female fetal sex (p = 0.003).

CONCLUSION

Our findings strengthen the hypothesis postulating that oxidative stress and mitochondrial dysfunction are key factors in the pathophysiology of PE. More prospective studies are highly warranted to further investigate the role of mtDNA in PE and assess the usefulness as a possible biomarker for PE.

Bisphenol A exposure alters placentation and causes preeclampsia-like features in pregnant mice involved in reprogramming of DNA methylation of WNT2

Preeclampsia leads to adverse outcomes for pregnant women. Bisphenol A (BPA) is an environmental endocrine disruptor and has been shown to be positively associated with increased risk of preeclampsia in human studies. We investigated whether BPA exposure causes preeclampsia-like features in pregnant mice and the associated underlying mechanisms. Experiments were performed in animal models and cell cultures. In pregnant mice, BPA-exposed mice exhibited preeclampsia-like features including hypertension, disruption of the circulation, and the placental angiogenesis biomarkers fms-related tyrosine kinase 1 and placenta growth factor, and glomerular atrophy; urinary protein was not affected. These preeclampsia-like features correlated with increased retention of smooth muscle cells and reduced vessel areas at the junctional zone of the placenta. In addition, there were disrupted expression of invasion-related genes including increased tissue inhibitors of metalloproteinases, decreased metalloproteinases, and Wnt family member WNT2/β-catenin, which correlated with increased DNA methylation in its promoter region and upregulation of DNA methyltransferase (Dnmt)1. BPA exposure impeded the interaction between the human cytotrophoblast cell line, HTR-8/SVneo, and endothelium cells. BPA exposure down-regulated WNT2 expression, and elevated the DNA methylation of WNT2; these results were consistent with in vivo observations. Inhibition of DNMT in HTR-8/SVneo cells resulted in reduced DNA methylation and increased expression of WNT2. Taken together, these data demonstrate that BPA exposure alters trophoblast cell invasion and causes abnormal placental vessel remodeling, both of which lead to the development of preeclampsia-like features in pregnant mice. Our results suggest that this phenomenon involves the epigenetic reprogramming and down-regulation of WNT2 mediated by DNMT1.-Ye, Y., Tang, Y., Xiong, Y., Feng, L., Li, X. Bisphenol A exposure alters placentation and causes preeclampsia-like features in pregnant mice involved in reprogramming of DNA methylation of WNT2.

Mitochondrial DNA Copy Number in Peripheral Blood in the First Trimester of Pregnancy and Different Preeclampsia Clinical Phenotypes Development: A Pilot Study

Inflammation and oxidative stress are intrinsically linked to early poor placentation, typical of pregnancies complicated by preeclampsia associated with intrauterine growth restriction (PE-IUGR). Low mitochondrial DNA copy number (mtDNAcn) in peripheral blood constitutes a good peripheral surrogate marker of inflammation and oxidative stress. On these basis, we explored a possible correlation between mtDNAcn in peripheral blood in the first trimester of pregnancy and the PE-IUGR onset. To shed light on this issue, we setup a nested case-control study from a prospective cohort of pregnant women undergoing first-trimester aneuploidies screening. Two groups of patients affected by PE classified according to the clinical phenotype were identified: (1) patients who developed PE-IUGR and (2) patients who developed PE associated with appropriate for gestational age intrauterine fetal growth (PE-AGAf). Controls were women with a physiologic pregnancy matched to cases on the basis of age (±6 months, ratio 2:1). Mitochondrial DNA copy number was quantified using real-time polymerase chain reaction and normalized to nuclear DNA. The median (interquartile range) mtDNAcn in peripheral blood in patients with PE-IUGR (n = 12) and in patients with PE-AGAf (n = 16) was 70 (44-97) and 108 (95-145), respectively (P = .004). Both these values were significantly lower than that detected in the control group (161[133-183], P < .001). The area under the receiver-operator curve for PE-IUGR and PE-AGAf were 0.94 (95% confidence interval [CI]: 0.88-1.00, P < .001) and 0.81 (95%CI: 0.70-0.91, P < .001), respectively. In conclusion, MtDNAcn in peripheral blood resulted significantly lower both in patients affected by PE-IUGR and in those affected by PE-AGAf when compared to controls. The accuracy of this biomarker resulted particularly good in predicting PE-IUGR.

Structure-Dependent Activity of Polybrominated Diphenyl Ethers and Their Hydroxylated Metabolites on Estrogen Related Receptor γ: in Vitro and in Silico Study

Estrogen-related receptor γ (ERRγ) is an orphan nuclear receptor having functional cross-talk with classical estrogen receptors. Here, we investigated whether ERRγ is a potential target of polybrominated diphenyl ethers (PBDEs) and their hydroxylated metabolites (OH-PBDEs). By using a fluorescence competitive binding method established in our laboratory, the binding potencies of 30 PBDEs/OH-PBDEs with ERRγ were determined for the first time. All of the tested OH-PBDEs and some PBDEs bound to ERRγ with K_d values ranging from 0.13-13.61 μM. The OH-PBDEs showed much higher binding potency than their parent PBDEs. A quantitative structure-activity relationship (QSAR) model was developed to analyze the chemical binding potencies in relation to their structural and chemical characteristics. The QSAR model indicated that the molecular size, relative ratios of aromatic atoms, and hydrogen bond donors and acceptors were crucial factors for PBDEs/OH-PBDEs binding. By using a reporter gene assay, we found that most of the low-brominated PBDEs/OH-PBDEs exerted agonistic activity toward ERRγ, while high-brominated PBDEs/OH-PBDEs had no effect on the basal ERRγ activity. The docking results showed that the low-brominated PBDEs/OH-PBDEs tended to take an agonistic binding mode while the high-brominated ones tended to take an antagonistic binding mode. Overall, our results suggest ERRγ to be a potential novel target for PBDEs/OH-PBDEs.

Estrogen-related receptor γ regulates expression of 17β-hydroxysteroid dehydrogenase type 1 in fetal growth restriction

INTRODUCTION

Estrogen-related receptor γ (ERRγ) and 17β-hydroxysteroid dehydrogenase type 1 (HSD17B1) have important roles in cell invasion and in the proliferation of many types of cancer cells. However, it remains unknown whether ERRγ and HSD17B1 contribute to abnormal placental structure and dysfunction which characterize fetal growth restriction (FGR). Therefore, the aim of this study was to investigate the expression profiles of ERRγ and HSD17B1 in placenta tissues affected by FGR and to examine a possible molecular mechanism by which ERRγ is able to regulate HSD17B1 during development of FGR.

METHODS

Placenta tissues were collected from women affected by FGR (n = 28) and from women with appropriately gestational age (AGA) (n = 30). Relative mRNA and protein levels of ERRγ and HSD17B1 in both groups were assessed by quantitative real-time PCR, immunohistochemistry, and Western blot analyses. The effect of ERRγ on trophoblast function and its associated mechanistic details were studied in the trophoblast cell line, HTR-8/SVneo, which was transfected with small interfering RNA (siRNA) targeting ERRγ.

RESULTS

Both mRNA and protein levels of ERRγ and HSD17B1 were significantly lower in FGR placentae (P < 0.05). When ERRγ expression was knocked down in HTR-8/SVneo cells with siRNA, invasion and proliferation were inhibited. In addition, HSD17B1 expression was significantly decreased. In dual luciferase reporter assays, ERRγ stimulated transcription of HSD17B1 by targeting the ERRγ response element within its 5'-flanking promoter region.

DISCUSSION

Aberrant ERRγ expression may contribute to the pathogenesis of FGR by regulating the transcriptional activity of HSD17B1.

Study of mitochondrial function in placental insufficiency

INTRODUCTION

It has been suggested that mitochondria play a crucial role in sustaining pregnancy and foetal growth. The aim of the study was to assess the influence of mitochondrial functions and genetics on placental insufficiency diseases.

METHODS

A total of 115 patients were recruited, subdivided into 74 placenta samples and 41 maternal blood samples: placental insufficiency diseases including intra uterine growth restriction (IUGR) (n = 35), preeclampsia (PE) (n = 13), IUGR associated to PE (PER) (n = 25); and controls (n = 42). Haplogroups were determined for all patients. Eighty-six placenta samples were studied for quantitative and qualitative analyses of mtDNA: IUGR (n = 25), PE (n = 1), PER (n = 18) and controls (n = 42). Sixteen placenta samples were selected for functional analysis: IUGR (n = 6), PER (n = 2) and controls (n = 8).

RESULTS

Mitochondrial DNA copy numbers and rearrangements and haplogroup distribution were not significantly altered in the patient group. Enzyme activity and expression of respiratory chain complexes were also comparable between both groups.

DISCUSSION

Our results do not argue in favour of a mitochondrial involvement in placental insufficiency, suggesting that the glycolytic pathway may represent a key energetic source in placental insufficiency diseases.

Pathophysiology of placental-derived fetal growth restriction

Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proliferation. These effects are compounded in more severe cases by increased infarction and fibrin deposition. Consequently, there is a reduction in villous volume and surface area for maternal-fetal exchange. Extensive dysregulation of imprinted and nonimprinted gene expression occurs, affecting placental transport, endocrine, metabolic, and immune functions. Secondary changes involving dedifferentiation of smooth muscle cells surrounding the fetal arteries within placental stem villi correlate with absent or reversed end-diastolic umbilical artery blood flow, and with a reduction in birthweight. Many of the morphological changes, principally the intraplacental vascular lesions, can be imaged using ultrasound or magnetic resonance imaging scanning, enabling their development and progression to be followed in vivo. The changes are more severe in cases of growth restriction associated with preeclampsia compared to those with growth restriction alone, consistent with the greater degree of maternal vasculopathy reported in the former and more extensive macroscopic placental damage including infarcts, extensive fibrin deposition and microscopic villous developmental defects, atherosis of the spiral arteries, and noninfectious villitis. The higher level of stress may activate proinflammatory and apoptotic pathways within the syncytiotrophoblast, releasing factors that cause the maternal endothelial cell activation that distinguishes between the 2 conditions. Congenital anomalies of the umbilical cord and placental shape are the only placental-related conditions that are not associated with maldevelopment of the uteroplacental circulation, and their impact on fetal growth is limited.

Impaired mitochondrial fusion, autophagy, biogenesis and dysregulated lipid metabolism is associated with preeclampsia

Preeclampsia(PE) is a pregnancy complication that is diagnosed by the new onset of hypertension and proteinuria. The etiology of PE remains unclear; however, growing evidence indicates that mitochondrial impairment contributes to the pathogenesis. Therefore, we aim to investigate the function of mitochondria in the development of PE. The mitochondrial metabolome in preeclamptic (n = 11) and normal (n = 11) placentas were analyzed using Gas chromatography-mass spectrometry (GC-MS). Student's t-tests and receiver operating characteristic (ROC) curves were conducted to determine which mitochondrial metabolites differed significantly between the two groups. The Pathway Activity Profiling (PAPi) R package was used to predict which metabolic pathways were affected by PE. Western blot analysis was performed to identify the candidate proteins which were associated with mitochondrial repair regulation. GC-MS analysis demonstrated that higher levels of 38 metabolites and lower levels of 2 metabolites were observed in the placenta of patients with severe PE (sPE). Five fatty acids had an area under the ROC curve above 90%. Furthermore, we revealed abnormal regulation of mitochondrial dynamics, autophagy, and biogenesis in sPE. Our discoveries indicate that the compromised lipid metabolism in sPE may result from dysfunctional mitochondria, thus revealing new insights into the etiology of the disease.

Mitochondrial [dys]function; culprit in pre-eclampsia?

Mitochondria are extensively identified for their bioenergetic capacities; however, recently these metabolic hubs are increasingly being appreciated as critical regulators of numerous cellular signalling systems. Mitochondrial reactive oxygen species have evolved as a mode of cross-talk between mitochondrial function and physiological systems, to sustain equipoise and foster adaption to cellular stress. Redox signalling mediated by exaggerated mitochondrial-ROS (reactive oxygen species) has been incriminated in a plethora of disease pathologies. Excessive production of mitochondrial ROS is intrinsically linked to mitochondrial dysfunction. Furthermore, mitochondrial dysfunction is a key facilitator of oxidative stress, inflammation, apoptosis and metabolism. These are key pathogenic intermediaries of pre-eclampsia, hence we hypothesize that mitochondrial dysfunction is a pathogenic mediator of oxidative stress in the pathophysiology of pre-eclampsia. We hypothesize that mitochondrial-targeted antioxidants may restrain production of ROS-mediated deleterious redox signalling pathways. If our hypothesis proves correct, therapeutic strategies directly targeting mitochondrial superoxide scavenging should be actively pursued as they may alleviate maternal vascular dysfunction and dramatically improve maternal and fetal health worldwide.

Mitochondrial DNA content and methylation in fetal cord blood of pregnancies with placental insufficiency

INTRODUCTION

Intrauterine growth restriction (IUGR) and preeclampsia (PE) are pregnancy disorders characterized by placental insufficiency with oxygen/nutrient restriction and oxidative stress, all influencing mitochondria functionality and number. Moreover, IUGR and PE fetuses are predisposed to diseases later in life, and this might occur through epigenetic alterations. Here we analyze content and methylation of mitochondrial DNA (mtDNA), for the first time in IUGR and PE singleton fetuses, to identify possible alterations in mtDNA levels and/or epigenetic control of mitochondrial loci relevant to replication (D-loop) and functionality (mt-TF/RNR1: protein synthesis, mt-CO1: respiratory chain complex).

METHODS

We studied 35 term and 8 preterm control, 31 IUGR, 17 PE/IUGR and 17 PE human singleton pregnancies with elective cesarean delivery. Fetal cord blood was collected and evaluated for biochemical parameters. Extracted DNA was subjected to Real-time PCR to assess mtDNA content and analyzed for D-loop, mt-TF/RNR1 and mt-CO1 methylation by bisulfite conversion and pyrosequencing.

RESULTS

mtDNA levels were increased in all pathologic groups compared to controls. Mitochondrial loci showed very low methylation levels in all samples; D-loop methylation was further decreased in the most severe cases and associated to umbilical vein pO₂. mt-CO1 methylation levels inversely correlated to mtDNA content.

DISCUSSION

Increased mtDNA levels in IUGR, PE/IUGR and PE cord blood may denote a fetal response to placental insufficiency. Hypomethylation of D-loop, mt-TF/RNR1 and mt-CO1 loci confirms their relevance in pregnancy.

Prenatal exposure to tobacco smoke leads to increased mitochondrial DNA content in umbilical cord serum associated to reduced gestational age

We investigated if prenatal exposures to tobacco smoke lead to changes in mitochondrial DNA content (mtDNA) in cord serum and adversely affect newborns' health. Umbilical cord serum cotinine levels were used to determine in utero exposure to smoking. Cord serum mtDNA was measured by quantitative polymerase chain reaction analysis of the genes coding for cytochrome c oxidase1 (MT-CO1) and cytochrome c oxidase2 (MT-CO2). Log transformed levels of mtDNA coding for MT-CO1 and MT-CO2 were significantly higher among infants of active smokers with higher serum level of cotinine (p < 0.05) and inversely associated with gestational age (p = 0.08; p = 0.02). Structural equation modeling results confirmed a positive association between cotinine and MT-CO1 and2 (p < 0.01) and inverse associations with gestational age (p = 0.02) and IGF-1 (p < 0.01). We identified a dose-dependent increase in the level of MT-CO1 and MT-CO2 associated to increased cord serum cotinine and decreased gestational age.

Review: Placental mitochondrial function and structure in gestational disorders

The aetiology of many gestational disorders is still unknown. However, insufficient trans-placental nutrient and oxygen transfer due to abnormal placentation is characteristic of several pathologies, and may alter the function of placental mitochondria. Mitochondria are multifunctional organelles that respond to a wide range of stimuli - such as physiological changes in cellular energy demands or various pathologies - by reshaping via fusion or fission, increasing/decreasing in number, altering oxidative phosphorylation, and signalling cellular functions such as apoptosis. Mitochondrial function is integral to tissue functions including energy production, metabolism, and regulation of various cellular responses including response to oxidative stress. This review details the functions of placental mitochondria and investigates mitochondrial function and structure in gestational disorders including preeclampsia, intrauterine growth restriction, diabetes mellitus, and obesity. Placental mitochondrial dysfunction may be critical in a range of gestational disorders which have important implications for maternal and fetal/offspring health.