Extracellular vesicles are dynamic regulators of maternal glucose homeostasis during pregnancy

Circulating extracellular vesicular microRNA signatures in early gestation show an association with subsequent clinical features of pre-eclampsia

In a prospective cohort of subjects who subsequently developed preeclampsia (PE, n = 14) versus remaining healthy (NORM, n = 12), early gestation circulating extracellular vesicles (EVs) containing a panel of microRNA signatures were characterized and their biological networks of targets deciphered. Multiple microRNAs of which some arose from the placenta (19MC and 14MC) demonstrated changes in association with advancing gestation, while others expressed were pathognomonic of the subsequent development of characteristic clinical features of PE which set in as a late-onset subtype. This panel of miRNAs demonstrated a predictability with an area under the curve of 0.96 using leave-one-out cross-validation training in a logistic regression model with elastic-net regularization and precautions against overfitting. In addition, this panel of miRNAs, some of which were previously detected in either placental tissue or as maternal cell-free non-coding transcripts, lent further validation to our EV studies and the observed association with PE. Further, the identified biological networks of targets of these detected miRNAs revealed biological functions related to vascular remodeling, cellular proliferation, growth, VEGF, EGF and the PIP3/Akt signaling pathways, all mediating key cellular functions. We conclude that we have demonstrated a proof-of-principle by detecting a panel of EV packaged miRNAs in the maternal circulation early in gestation with possibilities of biological function in the placenta and other maternal tissues, along with the probability of predicting the subsequent clinical appearance of PE, particularly the late-onset subtype.

Structural heteropatriarchy and maternal cardiovascular morbidities

The United States has some of the poorest maternal health outcomes of any developed nation. Existing research on maternal cardiovascular morbidities has focused predominantly on individual- and clinic-level drivers, but we know little about community- and structural-level factors that shape these outcomes. We use a composite measure of "structural heteropatriarchy" which includes measures of structural sexism and structural LGB-stigma to examine the relationship between structural heteropatriarchy and three cardiovascular-related maternal morbidities using the National Longitudinal Study of Adolescent to Adult Health (n = 3928). Results using multivariate regressions show that structural heteropatriarchy is associated with increased risk of reporting maternal morbidities. Our findings provide further evidence that sexuality- and gender-based stigma operate together to shape health disparities, including maternal health.

Streamlined Analysis of Maternal Plasma Indicates Small Extracellular Vesicles are Significantly Elevated in Early-Onset Preeclampsia

Preeclampsia (PE) is a leading cause of maternal and fetal mortality and morbidity. While placental dysfunction is a core underlying issue, the pathogenesis of this disorder is thought to differ between early-onset (EOPE) and late-onset (LOPE) subtypes. As recent reports suggest that small extracellular vesicles (sEVs) contribute to the development of PE, we have compared systemic sEV concentrations between normotensive, EOPE, and LOPE pregnancies. To circumvent lengthy isolation techniques and intermediate filtration steps, a streamlined approach was developed to evaluate circulating plasma sEVs from maternal plasma. Polymer-based precipitation and purification were used to isolate total systemic circulating maternal sEVs, free from bias toward specific surface marker expression or extensive subpurification. Immediate Nanoparticle Tracking Analysis (NTA) of freshly isolated sEV samples afforded a comprehensive analysis that can be completed within hours, avoiding confounding freeze-thaw effects of particle aggregation and degradation.Rather than exosomal subpopulations, our findings indicate a significant elevation in the total number of circulating maternal sEVs in patients with EOPE. This streamlined approach also preserves sEV-bound protein and microRNA (miRNA) that can be used for potential biomarker analysis. This study is one of the first to demonstrate that maternal plasma sEVs harbor full-length hypoxia inducible factor 1 alpha (HIF-1α) protein, with EOPE sEVs carrying higher levels of HIF-1α compared to control sEVs. The detection of HIF-1α and its direct signaling partner microRNA-210 (miR-210) within systemic maternal sEVs lays the groundwork for identifying how sEV signaling contributes to the development of preeclampsia. When taken together, our quantitative and qualitative results provide compelling evidence to support the translational potential of streamlined sEV analysis for future use in the clinical management of patients with EOPE.

Microorganism-derived extracellular vesicles: emerging contributors to female reproductive health

Extracellular vesicles (EVs) are cell-derived nanoparticles that carry small molecules, nucleic acids, and proteins long distances in the body facilitating cell-cell communication. Microorganism-derived EVs mediate communication between parent cells and host cells, with recent evidence supporting their role in biofilm formation, horizontal gene transfer, and suppression of the host immune system. As lipid-bound bacterial byproducts, EVs demonstrate improved cellular uptake and distribution in vivo compared to cell-free nucleic acids, proteins, or small molecules, allowing these biological nanoparticles to recapitulate the effects of parent cells and contribute to a range of human health outcomes. Here, we focus on how EVs derived from vaginal microorganisms contribute to gynecologic and obstetric outcomes. As the composition of the vaginal microbiome significantly impacts women's health, we discuss bacterial EVs from both healthy and dysbiotic vaginal microbiota. We also examine recent work done to evaluate the role of EVs from common vaginal bacterial, fungal, and parasitic pathogens in pathogenesis of female reproductive tract disease. We highlight evidence for the role of EVs in women's health, gaps in current knowledge, and opportunities for future work. Finally, we discuss how leveraging the innate interactions between microorganisms and mammalian cells may establish EVs as a novel therapeutic modality for gynecologic and obstetric indications.

Extracellular Vesicles in Pathophysiology: A Prudent Target That Requires Careful Consideration

Extracellular vesicles (EVs) are membrane-bound particles released by cells to perform multitudes of biological functions. Owing to their significant implications in diseases, the pathophysiological role of EVs continues to be extensively studied, leading research to neglect the need to explore their role in normal physiology. Despite this, many identified physiological functions of EVs, including, but not limited to, tissue repair, early development and aging, are attributed to their modulatory role in various signaling pathways via intercellular communication. EVs are widely perceived as a potential therapeutic strategy for better prognosis, primarily through utilization as a mode of delivery vehicle. Moreover, disease-associated EVs serve as candidates for the targeted inhibition by pharmacological or genetic means. However, these attempts are often accompanied by major challenges, such as off-target effects, which may result in adverse phenotypes. This renders the clinical efficacy of EVs elusive, indicating that further understanding of the specific role of EVs in physiology may enhance their utility. This review highlights the essential role of EVs in maintaining cellular homeostasis under different physiological settings, and also discusses the various aspects that may potentially hinder the robust utility of EV-based therapeutics.

Defining tropism and activity of natural and engineered extracellular vesicles

Extracellular vesicles (EVs) have important roles as mediators of cell-to-cell communication, with physiological functions demonstrated in various in vivo models. Despite advances in our understanding of the biological function of EVs and their potential for use as therapeutics, there are limitations to the clinical approaches for which EVs would be effective. A primary determinant of the biodistribution of EVs is the profile of proteins and other factors on the surface of EVs that define the tropism of EVs in vivo. For example, proteins displayed on the surface of EVs can vary in composition by cell source of the EVs and the microenvironment into which EVs are delivered. In addition, interactions between EVs and recipient cells that determine uptake and endosomal escape in recipient cells affect overall systemic biodistribution. In this review, we discuss the contribution of the EV donor cell and the role of the microenvironment in determining EV tropism and thereby determining the uptake and biological activity of EVs.

The 'communicatome' of pregnancy: spotlight on cellular and extravesicular chimerism

Communication via biological mediators between mother and fetus are key to reproductive success and offspring's future health. The repertoire of mediators coding signals between mother and fetus is broad and includes soluble factors, membrane-bound particles and immune as well as non-immune cells. Based on the emergence of technological advancements over the last years, considerable progress has been made toward deciphering the "communicatome" between fetus and mother during pregnancy and even after birth. In this context, pregnancy-associated chimerism has sparked the attention among immunologists, since chimeric cells-although low in number-are maintained in the allogeneic host (mother or fetus) for years after birth. Other non-cellular structures of chimerism, e.g. extracellular vesicles (EVs), are increasingly recognized as modulators of pregnancy outcome and offspring's health. We here discuss the origin, distribution and function of pregnancy-acquired microchimerism and chimeric EVs in mother and offspring. We also highlight the pioneering concept of maternal microchimeric cell-derived EVs in offspring. Such insights expand the understanding of pregnancy-associated health or disease risks in mother and offspring.

Extracellular vesicles as carriers of mRNA: Opportunities and challenges in diagnosis and treatment

Extracellular vesicles (EVs) are produced by all cells in the body. These biological nanoparticles facilitate cellular communication through the transport of diverse cargoes, including small molecules, proteins, and nucleic acids. mRNA cargoes have gained particular interest given their role in the translation of functional proteins. As a biomarker platform, EVs can be found in nearly all biofluids-blood, mucus, urine, cerebrospinal fluid, and saliva-providing real-time insight into parent cell and tissue function. mRNAs carried by EVs are protected from degradation, resulting in improved detection compared to free mRNA, and recent work demonstrates promising results in using these mRNA cargoes as biomarkers for cancer, neurological diseases, infectious diseases, and gynecologic and obstetric outcomes. Furthermore, given the innate cargo carrying, targeting, and barrier crossing abilities of EVs, these structures have been proposed as therapeutic carriers of mRNA. Recent advances demonstrate methods for loading mRNAs into EVs for a range of disease indications. Here, we review recent studies using EVs and their mRNA cargoes as diagnostics and therapeutics. We discuss challenges associated with EVs in diagnostic and therapeutic applications and highlight opportunities for future development.

Maternal-Infant Factors in Relation to Extracellular Vesicle and Particle miRNA in Prenatal Plasma and in Postpartum Human Milk

MicroRNAs (miRNA) in extracellular vesicles and particles (EVPs) in maternal circulation during pregnancy and in human milk postpartum are hypothesized to facilitate maternal-offspring communication via epigenetic regulation. However, factors influencing maternal EVP miRNA profiles during these two critical developmental windows remain largely unknown. In a pilot study of 54 mother-child dyads in the New Hampshire Birth Cohort Study, we profiled 798 EVP miRNAs, using the NanoString nCounter platform, in paired maternal second-trimester plasma and mature (6-week) milk samples. In adjusted models, total EVP miRNA counts were lower for plasma samples collected in the afternoon compared with the morning (p = 0.024). Infant age at sample collection was inversely associated with total miRNA counts in human milk EVPs (p = 0.040). Milk EVP miRNA counts were also lower among participants who were multiparous after delivery (p = 0.047), had a pre-pregnancy BMI > 25 kg/m2 (p = 0.037), or delivered their baby via cesarean section (p = 0.021). In post hoc analyses, we also identified 22 specific EVP miRNA that were lower among participants who delivered their baby via cesarean section (Q < 0.05). Target genes of delivery mode-associated miRNAs were over-represented in pathways related to satiety signaling in infants (e.g., CCKR signaling) and mammary gland development and lactation (e.g., FGF signaling, EGF receptor signaling). In conclusion, we identified several key factors that may influence maternal EVP miRNA composition during two critical developmental windows, which should be considered in future studies investigating EVP miRNA roles in maternal and child health.

Multiple Particle Tracking: A Method for Probing Biologically Relevant Mobility of Bacterial Extracellular Vesicles

Bacterial extracellular vesicles (bEVs) are produced by both Gram-negative and Gram-positive bacteria. These biological nanoparticles transport small molecules, nucleic acids, and proteins, enabling communication with both bacterial and mammalian cells. bEVs can evade and disrupt biological barriers, and their lipid membranes protect their cargo from degradation, facilitating long-distance communication in vivo. Furthermore, bacteria are easily manipulated and easily cultured. These combined factors make bEVs an ideal candidate for drug delivery applications. Thus, the study of how bEVs interact with biological barriers is interesting from both a signaling and drug delivery perspective. Here we describe methods for tracking bEV motion in biological matrices ex vivo. We outline methods for growth, isolation, quantification, and labeling, as well as techniques for tracking bEV motion ex vivo and quantifying these data. The methods described here are relevant to bEV communication with host cells as well as drug delivery applications using bEVs.

Maternal-fetal cross-talk via the placenta: influence on offspring development and metabolism

Compelling epidemiological and animal experimental data demonstrate that cardiometabolic and neuropsychiatric diseases originate in a suboptimal intrauterine environment. Here, we review evidence suggesting that altered placental function may, at least in part, mediate the link between the maternal environment and changes in fetal growth and development. Emerging evidence indicates that the placenta controls the development and function of several fetal tissues through nutrient sensing, modulation of trophoblast nutrient transporters and by altering the number and cargo of released extracellular vesicles. In this Review, we discuss the development and functions of the maternal-placental-fetal interface (in humans and mice) and how cross-talk between these compartments may be a mechanism for in utero programming, focusing on mechanistic target of rapamycin (mTOR), adiponectin and O-GlcNac transferase (OGT) signaling. We also discuss how maternal diet and stress influences fetal development and metabolism and how fetal growth restriction can result in susceptibility to developing chronic disease later in life. Finally, we speculate how interventions targeting placental function may offer unprecedented opportunities to prevent cardiometabolic disease in future generations.

O-GlcNAc Dynamics: The Sweet Side of Protein Trafficking Regulation in Mammalian Cells

The transport of proteins between the different cellular compartments and the cell surface is governed by the secretory pathway. Alternatively, unconventional secretion pathways have been described in mammalian cells, especially through multivesicular bodies and exosomes. These highly sophisticated biological processes rely on a wide variety of signaling and regulatory proteins that act sequentially and in a well-orchestrated manner to ensure the proper delivery of cargoes to their final destination. By modifying numerous proteins involved in the regulation of vesicular trafficking, post-translational modifications (PTMs) participate in the tight regulation of cargo transport in response to extracellular stimuli such as nutrient availability and stress. Among the PTMs, O-GlcNAcylation is the reversible addition of a single N-acetylglucosamine monosaccharide (GlcNAc) on serine or threonine residues of cytosolic, nuclear, and mitochondrial proteins. O-GlcNAc cycling is mediated by a single couple of enzymes: the O-GlcNAc transferase (OGT) which catalyzes the addition of O-GlcNAc onto proteins, and the O-GlcNAcase (OGA) which hydrolyses it. Here, we review the current knowledge on the emerging role of O-GlcNAc modification in the regulation of protein trafficking in mammalian cells, in classical and unconventional secretory pathways.