Endothelial cell diversity: the many facets of the crystal

Endothelial cells (ECs) form the inner lining of blood vessels and play crucial roles in angiogenesis. While it has been known for a long time that there are considerable differences among ECs from lymphatic and blood vessels, as well as among arteries, veins and capillaries, the full repertoire of endothelial diversity is only beginning to be elucidated. It has become apparent that the role of ECs is not just limited to their exchange functions. Indeed, a multitude of organ-specific functions, including release of growth factors, regulation of immune functions, have been linked to ECs. Recent years have seen a surge into the identification of spatiotemporal molecular and functional heterogeneity of ECs, supported by technologies such as single-cell RNA sequencing (scRNA-seq), lineage tracing and intersectional genetics. Together, these techniques have spurred the generation of epigenomic, transcriptomic and proteomic signatures of ECs. It is now clear that ECs across organs and in different vascular beds, but even within the same vessel, have unique molecular identities and employ specialized molecular mechanisms to fulfil highly specialized needs. Here, we focus on the molecular heterogeneity of the endothelium in different organs and pathological conditions.

First-trimester urinary extracellular vesicles as predictors of preterm birth: an insight into immune programming

Background: The programming of innate and adaptive immunity plays a pivotal role in determining the course of pregnancy, leading to either normal term birth (TB) or preterm birth (PB) through the modulation of macrophage (M1/M2) differentiation. Extracellular vesicles (EVs) in maternal blood, harboring a repertoire of physiological and pathological messengers, are integral players in pregnancy outcomes. It is unknown whether urinary EVs (UEVs) could serve as a non-invasive mechanistic biomarker for predicting PB. Methods: This study investigated first-trimester UEVs carrying M1 messengers with altered immune programming, aiming to discern their correlation to subsequent PB. A birth cohort comprising 501 pregnant women, with 40 women experiencing PB matched to 40 women experiencing TB on the same day, was examined. First-trimester UEVs were isolated for the quantification of immune mediators. Additionally, we evaluated the UEV modulation of "trained immunity" on macrophage and lymphocyte differentiations, including mRNA expression profiles, and chromatin activation modification at histone 3 lysine 4 trimethylation (H3K4me3). Results: We found a significant elevation (p < 0.05) in the particles of UEVs bearing characteristic exosome markers (CD9/CD63/CD81/syntenin) during the first trimester of pregnancy compared to non-pregnant samples. Furthermore, UEVs from PB demonstrated significantly heightened levels of MCP-1 (p = 0.003), IL-6 (p = 0.041), IL-17A (p = 0.007), IP-10 (p = 0.036), TNFα (p = 0.004), IL-12 (p = 0.045), and IFNγ (p = 0.030) relative to those from TB, indicative of altered M1 and Th17 differentiation. Notably, MCP-1 (>174 pg/mL) exhibited a sensitivity of 71.9% and specificity of 64.6%, and MCP-1 (>174 pg/mL) and IFNγ (>8.7 pg/mL) provided a higher sensitivity (84.6%) of predicting PB and moderate specificity of 66.7%. Subsequent investigations showed that UEVs from TB exerted a significant suppression of M1 differentiation (iNOS expression) and Th17 differentiation (RORrT expression) compared to those of PB. Conversely, UEVs derived from PB induced a significantly higher expression of chromatin modification at H3K4me3 with higher production of IL-8 and TNFα cytokines (p < 0.001). Implications: This pioneering study provides critical evidence for the early detection of altered M1 and Th17 responses within UEVs as a predictor of PB and early modulation of altered M1 and Th17 polarization associated with better T-cell regulatory differentiation as a potential prevention of subsequent PB.

Impaired decidualization and relative increase of PROK1 expression in the decidua of patients with unexplained recurrent pregnancy loss showing insulin resistance

A recent meta-analysis revealed that patients with unexplained recurrent pregnancy loss (RPL) show higher insulin resistance compared to healthy controls. However, the etiology of RPL remains unknown. Prokineticin (PROK1), a pleiotropic uterine endometrial protein, is important for implantation and decidualization and is regulated by hypoxia and insulin. In this study, we investigated the decidualization status and the role of PROK1 in the decidua of patients with unexplained RPL showing insulin resistance. Thirty-two patients with unexplained RPL were included in this study. Following the diagnosis of a miscarriage, the decidua and villi of the patient were surgically collected. Fasting blood glucose and insulin levels were measured, and HOMA-β was calculated. Using IHC and ELISA, the expression of IGFBP-1, PRL and PROK1 in the decidua and IGF-2 in the villi were analyzed in patients with euploid miscarriage with a high HOMA-β index (n = 8) and compared to controls (euploid miscarriage with normal HOMA-β: n = 12, aneuploid miscarriage with normal HOMA-β: n = 12). The co-localization of PROK1 and IGFBP-1 was observed in the decidua by IHC. In the decidua of RPL patients with high HOMA-β, the expression levels of IGFBP-1 and PRL were significantly lower, whereas the PROK1/IGFBP-1 ratio was significantly higher compared to that of the controls. IGF-2 expression in villi was significantly lower in RPL patients with high HOMA-β. Impaired decidualization and excessive PROK1 production may have pathological implications in patients with unexplained RPL with insulin resistance, especially under the state of hyper insulin production.

EG-VEGF maternal levels predict spontaneous preterm birth in the second and third trimesters in pregnant women with risk factors for placenta-mediated complications

Prediction of spontaneous preterm birth in asymptomatic women remains a great challenge for the public health system. The aim of the study was to determine the informational value of EG-VEGF circulating levels for prediction of spontaneous preterm birth in the second and third trimesters in pregnant women at high risk for placenta-mediated complications. A prospective multicenter cohort study including 200 pregnant patients with five-serum sampling per patient. Women with spontaneous preterm birth have higher concentrations of serum EG-VEGF than uncomplicated patients at 24 weeks, 28 weeks and 32 weeks (p = 0.03, 0.02 and < 0.001). The areas under the curve reached 0.9 with 100% sensitivity at 32 weeks for the prediction of spontaneous preterm birth. Serum EG-VEGF concentrations could be considered as a reliable biomarker of spontaneous preterm birth in high-risk for placenta-mediated complications pregnant women.

Therapeutic Potential of Targeting Prokineticin Receptors in Diseases

The prokineticins (PKs) were discovered approximately 20 years ago as small peptides inducing gut contractility. Today, they are established as angiogenic, anorectic, and proinflammatory cytokines, chemokines, hormones, and neuropeptides involved in variety of physiologic and pathophysiological pathways. Their altered expression or mutations implicated in several diseases make them a potential biomarker. Their G-protein coupled receptors, PKR1 and PKR2, have divergent roles that can be therapeutic target for treatment of cardiovascular, metabolic, and neural diseases as well as pain and cancer. This article reviews and summarizes our current knowledge of PK family functions from development of heart and brain to regulation of homeostasis in health and diseases. Finally, the review summarizes the established roles of the endogenous peptides, synthetic peptides and the selective ligands of PKR1 and PKR2, and nonpeptide orthostatic and allosteric modulator of the receptors in preclinical disease models. The present review emphasizes the ambiguous aspects and gaps in our knowledge of functions of PKR ligands and elucidates future perspectives for PK research. SIGNIFICANCE STATEMENT: This review provides an in-depth view of the prokineticin family and PK receptors that can be active without their endogenous ligand and exhibits "constitutive" activity in diseases. Their non- peptide ligands display promising effects in several preclinical disease models. PKs can be the diagnostic biomarker of several diseases. A thorough understanding of the role of prokineticin family and their receptor types in health and diseases is critical to develop novel therapeutic strategies with safety concerns.

Isolation and characterization human chorion membrane trophoblast and mesenchymal cells

INTRODUCTION

To develop protocols for isolation and culture of human chorionic mesenchymal and trophoblast cells and test their differential responsiveness to oxidative stress.

METHODS

Chorion trophoblast cells (CTC) and chorion mesenchymal cells (CMC) were isolated from term fetal membranes by modifying current protocols. Their purity and characteristics were tested using bright field microscopy and after staining for cytokeratin (CK)-7 and vimentin. Cigarette smoke extract (CSE) was used to stimulate cells, and we determined reactive oxygen species (ROS) production using 2'7'-dichlorodihydro-fluorescein assay, stress signaler p38MAPK activation (Western blot) and senescence by flow cytometry. Co-treatment with antioxidant N-acetyl cystine (NAC) either alone or in combination with SB203580 (p38MAPK inhibitor) was used to test oxidative stress (OS)- and p38MAPK-mediated effects.

RESULTS

The isolation and cell culture protocol used in this study yielded 92% pure CTC and 100% pure CMC. CSE treatment significantly induced ROS production, P-p38MAPK activation, and senescence in both cell types compared to controls. Cotreatment with NAC reduced ROS production and p38MAPK activation, and co-treatment with both NAC and SB203580 reduced senescence. ROS response in CMC was higher than CTC; however, senescence of CTC was 10-fold higher than CMC.

CONCLUSIONS

We introduce approaches for proper isolation and culture of CTC and CMC without any influence or overgrowth of one specific type cell that can confound results. Using this approach, we determined differential effects of CTC and CMC to OS condition seen at term labor. Both CTC and CMC undergo p38MAPK-mediated senescence; however, the rate of senescence is higher in CTC.

Novel pathways of inflammation in human fetal membranes associated with preterm birth and preterm pre-labor rupture of the membranes

Spontaneous preterm birth (PTB) and preterm pre-labor rupture of the membranes (pPROM) are major pregnancy complications. Although PTB and pPROM have common etiologies, they arise from distinct pathophysiologic pathways. Inflammation is a common underlying mechanism in both conditions. Balanced inflammation is required for fetoplacental growth; however, overwhelming inflammation (physiologic at term and pathologic at preterm) can lead to term and preterm parturition. A lack of effective strategies to control inflammation and reduce the risk of PTB and pPROM suggests that there are several modes of the generation of inflammation which may be dependent on the type of uterine tissue. The avascular fetal membrane (amniochorion), which provides structure, support, and protection to the intrauterine cavity, is one of the key contributors of inflammation. Localized membrane inflammation helps tissue remodeling during pregnancy. Two unique mechanisms that generate balanced inflammation are the progressive development of senescence (aging) and cyclic cellular transitions: epithelial to mesenchymal (EMT) and mesenchymal to epithelial (MET). The intrauterine build-up of oxidative stress at term or in response to risk factors (preterm) can accelerate senescence and promote a terminal state of EMT, resulting in the accumulation of inflammation. Inflammation degrades the matrix and destabilizes membrane function. Inflammatory mediators from damaged membranes are propagated via extracellular vesicles (EV) to maternal uterine tissues and transition quiescent maternal uterine tissues into an active state of labor. Membrane inflammation and its propagation are fetal signals that may promote parturition. This review summarizes the mechanisms of fetal membrane cellular senescence, transitions, and the generation of inflammation that contributes to term and preterm parturitions.

The Prokineticins: Neuromodulators and Mediators of Inflammation and Myeloid Cell-Dependent Angiogenesis

The mammalian prokineticins family comprises two conserved proteins, EG-VEGF/PROK1 and Bv8/PROK2, and their two highly related G protein-coupled receptors, PKR1 and PKR2. This signaling system has been linked to several important biological functions, including gastrointestinal tract motility, regulation of circadian rhythms, neurogenesis, angiogenesis and cancer progression, hematopoiesis, and nociception. Mutations in PKR2 or Bv8/PROK2 have been associated with Kallmann syndrome, a developmental disorder characterized by defective olfactory bulb neurogenesis, impaired development of gonadotropin-releasing hormone neurons, and infertility. Also, Bv8/PROK2 is strongly upregulated in neutrophils and other inflammatory cells in response to granulocyte-colony stimulating factor or other myeloid growth factors and functions as a pronociceptive mediator in inflamed tissues as well as a regulator of myeloid cell-dependent tumor angiogenesis. Bv8/PROK2 has been also implicated in neuropathic pain. Anti-Bv8/PROK2 antibodies or small molecule PKR inhibitors ameliorate pain arising from tissue injury and inhibit angiogenesis and inflammation associated with tumors or some autoimmune disorders.

Prokineticins and their G protein-coupled receptors in health and disease

Prokineticins are two conserved small proteins (~8kDa), prokineticin 1 (PROK1; also called EG-VEGF) and prokineticin 2 (PROK2; also called Bv8), with an N-terminal AVITGA sequence and 10 cysteines forming 5 disulfide bridges. PROK1 and PROK2 bind to two highly related G protein-coupled receptors (GPCRs), prokineticin receptor 1 (PROKR1) and prokineticin receptor 2 (PROKR2). Prokineticins and their receptors are widely expressed. PROK1 is predominantly expressed in peripheral tissues, especially steroidogenic organs, whereas PROK2 is mainly expressed in the central nervous system and nonsteroidogenic cells of the testes. Prokineticins signaling has been implicated in several important physiological functions, including gastrointestinal smooth muscle contraction, circadian rhythm regulation, neurogenesis, angiogenesis, pain perception, mood regulation, and reproduction. Dysregulation of prokineticins signaling has been observed in a variety of diseases, such as cancer, ischemia, and neurodegeneration, in which prokineticins signaling seems to be a promising therapeutic target. Based on the phenotypes of knockout mice, PROKR2 and PROK2 have recently been identified as causative genes for idiopathic hypogonadotropic hypogonadism, a developmental disorder characterized by impaired development of gonadotropin-releasing hormone neurons and infertility. In vitro functional studies with these disease-associated PROKR2 mutations uncovered some novel features for this receptor, such as biased signaling, which may be used to understand GPCR signaling regulation in general.

Relationship between second-trimester amniotic fluid levels of Prokineticin-1 and Matrix Metalloproteinase-2 with adverse pregnancy outcome

To investigate the levels of Prokineticin-1 (PROK1) and matrix metalloproteinase-2 (MMP-2) in second-trimester amniotic fluid (AF). AF samples were investigated in 81 patients. AF-PROK1 and AF-MMP-2 were not significantly associated with adverse pregnancy outcomes (preeclampsia, intrauterine growth retardation, spontaneous preterm birth, gestational diabetes, gestational hypertension). AF-PROK1 levels in patients with abnormal first-trimester screening were significantly higher than those who underwent amniocentesis due to abnormal second-trimester screening tests (p = .04). AF-PROK1 or AF-MMP-2 do not have a role in the prediction of adverse pregnancy outcomes.

Use of prokineticin-1 (PROK1), pregnancy-associated plasma protein A (PAPP-A) and PROK1/PAPP-A ratio to predict adverse pregnancy outcomes in the first trimester: a prospective study

INTRODUCTION

To compare the predictive effectiveness levels of prokineticin-1 (PROK1), pregnancy-associated plasma protein A (PAPP-A) and the PROK1/PAPP-A ratio in the first trimester for preeclampsia (PE), foetal growth restriction (FGR), gestational diabetes mellitus (GDM) and spontaneous preterm birth (SPB).

MATERIALS AND METHODS

A total of randomly selected 162 pregnant women were included. Peripheral blood samples were obtained between 11^0/7 and 13^6/7 gestational weeks (GWs). All women were followed throughout the pregnancy and classified into five groups as having PE, FGR, GDM, SPB and uncomplicated pregnancies. The cut-off levels of the markers were identified to predict adverse outcomes.

RESULTS

PROK1 predicted PE with 83.3% sensitivity, 85.7% specificity at a value of >293.4 pg/mL; at a value of >260.2 pg/mL, PROK1 predicted FGR with 85.7% sensitivity, 72.5% specificity in the first trimester. The area under receiver operating characteristic (ROC) curve of PAPP-A was lower than that of PROK1 and PROK1/PAPP-A in differentiating PE and FGR from the uncomplicated group (p < .001). PROK1 levels and the PROK1/PAPP-A ratios in the SPB and GDM groups were lower than in the uncomplicated group (p < .01).

CONCLUSIONS

Elevated PROK1 in the first trimester is a more effective marker than PAPP-A in the prediction of PE and FGR. Lower PROK1 levels are associated with the development of SPB and GDM.

Diagnostic Performance of Placental Growth Factor in Women With Suspected Preeclampsia Attending Antenatal Facilities in Maputo, Mozambique

In well-resourced settings, reduced circulating maternal-free placental growth factor (PlGF) aids in either predicting or confirming the diagnosis of preeclampsia, fetal growth restriction, stillbirth, preterm birth, and delivery within 14 days of testing when preeclampsia is suspected. This blinded, prospective cohort study of maternal plasma PlGF in women with suspected preeclampsia was conducted in antenatal clinics in Maputo, Mozambique. The primary outcome was the clinic-to-delivery interval. Other outcomes included: confirmed diagnosis of preeclampsia, transfer to higher care, mode of delivery, intrauterine fetal death, preterm birth, and low birth weight. Of 696 women, 95 (13.6%) and 601 (86.4%) women had either low (<100 pg/mL) or normal (≥100 pg/mL) plasma PlGF, respectively. The clinic-to-delivery interval was shorter in low PlGF, compared with normal PlGF, women (median 24 days [interquartile range, 10-49] versus 44 [24-81], P=0.0042). Also, low PlGF was associated with a confirmed diagnosis of preeclampsia, higher blood pressure, transfer for higher care, earlier gestational age delivery, delivery within 7 and 14 days, preterm birth, cesarean delivery, lower birth weight, and perinatal loss. In urban Mozambican women with symptoms or signs suggestive of preeclampsia, low maternal plasma PlGF concentrations are associated with increased risks of adverse pregnancy outcomes, whether the diagnosis of preeclampsia is confirmed. Therefore, PlGF should improve the provision of precision medicine to individual women and improve pregnancy outcomes for those with preeclampsia or related placenta-mediated complications.

Prokineticin1 and pregnancy

Prokineticin 1 (PROK1), also called EG-VEGF, is a peptide of 86 amino acids with multiple biological functions. PROK1 acts via two G-protein coupled receptors: PROKR1 PROKR2. PROK1 is highly expressed in the placenta. This article reports the expression and the role of PROK1 during normal and pathological pregnancies: (i) during early pregnancy, PROK1 exhibits a peak of placental expression shortly before the establishment of the feto-maternal circulation; (ii) its receptors, PROKR1 PROKR2 are highly expressed in human placenta; (iii) its expression is increased by hypoxia; (iv) PROK1 inhibits extravillous trophoblasts migration and invasion and increases their proliferation and survival; (v) PROK1 is also a pro-angiogenic placental factor that increases microvascular placental endothelial cells proliferation, migration, invasion, and permeability. Circulating PROK1 levels are five times higher in pregnant women during the first trimester compared to the second and third trimesters. Also, its serum levels are higher in patients with preeclampsia (PE) and in patients with isolated intra-uterine growth restriction (IUGR). In mice, maintaining high level of PROK1 beyond its normal period of production (>10.5dpc) reproduces symptoms of PE. To date, our results demonstrated that PROK1 is a central factor of human placentation with direct roles both in the control of trophoblast invasion and villous growth. Thus, a failure in the expression of PROK1 and/or its receptor during pregnancy may contribute to the development of PE and/or IUGR. Besides theses original findings, we also report a direct role of this factor in parturition.