Extracellular vesicle-associated miRNAs are an adaptive response to gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is a serious public health issue affecting 9-15% of all pregnancies worldwide. Recently, it has been suggested that extracellular vesicles (EVs) play a role throughout gestation, including mediating a placental response to hyperglycaemia. Here, we investigated the EV-associated miRNA profile across gestation in GDM, assessed their utility in developing accurate, multivariate classification models, and determined the signaling pathways in skeletal muscle proteome associated with the changes in the EV miRNA profile.

METHODS

Discovery: A retrospective, case-control study design was used to identify EV-associated miRNAs that vary across pregnancy and clinical status (i.e. GDM or Normal Glucose Tolerance, NGT). EVs were isolated from maternal plasma obtained at early, mid and late gestation (n = 29) and small RNA sequencing was performed. Validation: A longitudinal study design was used to quantify expression of selected miRNAs. EV miRNAs were quantified by real-time PCR (cases = 8, control = 14, samples at three times during pregnancy) and their individual and combined classification efficiencies were evaluated. Quantitative, data-independent acquisition mass spectrometry was use to establish the protein profile in skeletal muscle biopsies from normal and GDM.

RESULTS

A total of 2822 miRNAs were analyzed using a small RNA library, and a total of 563 miRNAs that significantly changed (p < 0.05) across gestation and 101 miRNAs were significantly changed between NGT and GDM. Analysis of the miRNA changes in NGT and GDM separately identified a total of 256 (NGT-group), and 302 (GDM-group) miRNAs that change across gestation. A multivariate classification model was developed, based on the quantitative expression of EV-associated miRNAs, and the accuracy to correctly assign samples was > 90%. We identified a set of proteins in skeletal muscle biopsies from women with GDM associated with JAK-STAT signaling which could be targeted by the miRNA-92a-3p within circulating EVs. Interestingly, overexpression of miRNA-92a-3p in primary skeletal muscle cells increase insulin-stimulated glucose uptake.

CONCLUSIONS

During early pregnancy, differently-expressed, EV-associated miRNAs may be of clinical utility in identifying presymptomatic women who will subsequently develop GDM later in gestation. We suggest that miRNA-92a-3p within EVs might be a protected mechanism to increase skeletal muscle insulin sensitivity in GDM.

miRNa signature in small extracellular vesicles and their association with platinum resistance and cancer recurrence in ovarian cancer

Carboplatin, administered as a single drug or in combination with paclitaxel, is the standard chemotherapy treatment for patients with ovarian cancer (OVCA). Recent evidence suggests that miRNAs associated with small extracellular vesicles (sEVs) participate in the development of chemoresistance. We studied the effect of carboplatin in a heterogeneity population of OVCA cells and their derived sEVs to identify mechanisms associated with chemoresistance. sEVs were quantified using an engineered superparamagnetic material, gold-loaded ferric oxide nanotubes and a screen-printed electrode. miR-21-3p, miR-21-5p, and miR-891-5p are enriched in sEVs, and they contribute to carboplatin resistance in OVCA. Using a quantitative MS/MS, miR-21-5p activates glycolysis and increases the expression of ATP-binding cassette family and a detoxification enzyme. miR-21-3p and miR-891-5p increase the expression of proteins involved in DNA repair mechanisms. Interestingly, the levels of miR-891-5p within sEVs are significantly higher in patients at risk of ovarian cancer relapse. Identification of miRNAs in sEVs also provides the opportunity to track them in biological fluids to potentially determine patient response to chemotherapy.

Protein Profile Changes in Circulating Placental Extracellular Vesicles in Term and Preterm Births: A Longitudinal Study

Spontaneous preterm birth (PTB) is a major obstetrical problem around the globe and the mechanisms leading to PTB are unclear. Recently, changes in the circulating levels of placental extracellular vesicles (EVs) during pregnancy have been associated with various pregnancy complications. However, progress in the field is hindered by the inability to isolate placental EVs from the maternal circulation. A longitudinal study design was used to determine the protein cargo present in circulating placental EVs in maternal plasma of term and PTB across gestation (ie, first, second, and third trimester). Placental-derived EVs were enriched from the total EV population based on their expression of membrane-bound placental alkaline phosphatase (PLAP). A quantitative, information-independent acquisition (sequential windowed acquisition of all theoretical mass spectra [SWATH]) approach identified and quantified the placental EV protein contents. PLAP+ EVs did not change in characteristics (size, shape, and markers) but did differ in numbers across gestation with low levels in PTB. A comparison analysis between the PLAP+ EV proteome from term and PTB revealed 96 proteins differing significantly (P < 0.05, false discovery rate 1%) across gestation. Bioinformatics analysis of differentially expressed proteins revealed consistent upregulation of inflammatory pathways in both upregulation of epithelial mesenchymal transition pathways at term and downregulation of coagulation/complement activation in preterm. Characterization of the proteomic profile in PLAP+ EVs across gestation demonstrates dramatic changes, which might be used to understand the biological process associated with early parturition and develop biomarkers for predicting high-risk status for PTB.

Quantitative Proteomics by SWATH-MS Suggest an Association Between Circulating Exosomes and Maternal Metabolic Changes in Gestational Diabetes Mellitus

Several factors including placental hormones (PH) released from the human placenta have been associated with the development of insulin resistance and gestational diabetes mellitus (GDM). However, circulating levels of PH does not correlate well with maternal insulin sensitivity across gestation, suggesting that other, previously unrecognized, mechanisms may be involved. The levels of circulating exosomes are higher in GDM compared to normal. GDM derived exosomes produce greater release of pro-inflammatory cytokines from endothelial cells compared to exosomes from normal, suggesting that their contents may differ compared to normal pregnancies. Using a quantitative, information-independent acquisition (Sequential Windowed Acquisition of All Theoretical Mass Spectra [SWATH]) approach, differentially abundant circulating exosome proteins are identified in women with normal glucose tolerance (NGT) and GDM at the time of GDM diagnosis. A total of 78 statistically significant proteins in the relative expression of exosomal proteins in GDM are compared with NGT. Bioinformatic analysis shows that the exosomal proteins in GDM target pathways are mainly associated with energy production, inflammation, and metabolism. Finally, an independent cohort of patients is used to validate some of the proteins identified by SWATH. The data obtained may be of utility in elucidating the underlying physiological mechanisms associated with insulin resistance in GDM.

Downregulation of exosomal miR-192-5p and miR-204-5p in subjects with nonclassic apparent mineralocorticoid excess

BACKGROUND

The "nonclassic" apparent mineralocorticoid excess (NC-AME) has been identified in approximately 7% of general population. This phenotype is characterized by low plasma renin activity (PRA), high serum cortisol (F) to cortisone (E) ratio, low cortisone, high Fractional Excretion of potassium (FEK) and normal-elevated systolic blood pressure (SBP). An early detection and/or identification of novel biomarkers of this phenotype could avoid the progression or future complications leading to arterial hypertension. Isolation of extracellular vesicles, such as exosomes, in specific biofluids support the identification of tissue-specific RNA and miRNA, which may be useful as novel biomarkers. Our aim was to identify miRNAs within urinary exosomes associated to the NC-AME phenotype.

METHODS

We perform a cross-sectional study in a primary care cohort of 127 Chilean subjects. We measured BP, serum cortisol, cortisone, aldosterone, PRA. According to the previous reported, a subgroup of subjects was classified as NC-AME (n = 10). Urinary exosomes were isolated and miRNA cargo was sequenced by Illumina-NextSeq-500.

RESULTS

We found that NC-AME subjects had lower cortisone (p < 0.0001), higher F/E ratio (p < 0.0001), lower serum potassium (p = 0.009) and higher FEK 24 h (p = 0.03) than controls. We found miR-204-5p (fold-change = 0.115; p 0.001) and miR-192-5p (fold-change = 0.246; p 0.03) are both significantly downregulated in NC-AME. miR-192-5p expression was correlated with PRA (r = 0.45; p 0.028) and miR-204-5p expression with SBP (r = - 0.48, p 0.027) and F/E ratio (r = - 0.48; p 0.026).

CONCLUSIONS

These findings could support a potential role of these miRNAs as regulators and novel biomarkers of the NC-AME phenotype.

DNA Methylation Cancer Biomarkers: Translation to the Clinic

Carcinogenesis is accompanied by widespread DNA methylation changes within the cell. These changes are characterized by a globally hypomethylated genome with focal hypermethylation of numerous 5’-cytosine-phosphate-guanine-3’ (CpG) islands, often spanning gene promoters and first exons. Many of these epigenetic changes occur early in tumorigenesis and are highly pervasive across a tumor type. This allows DNA methylation cancer biomarkers to be suitable for early detection and also to have utility across a range of areas relevant to cancer detection and treatment. Such tests are also simple in construction, as only one or a few loci need to be targeted for good test coverage. These properties make cancer-associated DNA methylation changes very attractive for development of cancer biomarker tests with substantive clinical utility. Across the patient journey from initial detection, to treatment and then monitoring, there are several points where DNA methylation assays can inform clinical practice. Assays on surgically removed tumor tissue are useful to determine indicators of treatment resistance, prognostication of outcome, or to molecularly characterize, classify, and determine the tissue of origin of a tumor. Cancer-associated DNA methylation changes can also be detected with accuracy in the cell-free DNA present in blood, stool, urine, and other biosamples. Such tests hold great promise for the development of simple, economical, and highly specific cancer detection tests suitable for population-wide screening, with several successfully translated examples already. The ability of circulating tumor DNA liquid biopsy assays to monitor cancer in situ also allows for the ability to monitor response to therapy, to detect minimal residual disease and as an early biomarker for cancer recurrence. This review will summarize existing DNA methylation cancer biomarkers used in clinical practice across the application domains above, discuss what makes a suitable DNA methylation cancer biomarker, and identify barriers to translation. We discuss technical factors such as the analytical performance and product-market fit, factors that contribute to successful downstream investment, including geography, and how this impacts intellectual property, regulatory hurdles, and the future of the marketplace and healthcare system.

Adipose Tissue Exosomal Proteomic Profile Reveals a Role on Placenta Glucose Metabolism in Gestational Diabetes Mellitus

CONTEXT

Molecules produced by adipose tissue (AT) function as an endocrine link between maternal AT and fetal growth by regulating placental function in normal women and women with gestational diabetes mellitus (GDM).

OBJECTIVE

We hypothesized that AT-derived exosomes (exo-AT) from women with GDM would carry a specific set of proteins that influences glucose metabolism in the placenta.

DESIGN

Exosomes were isolated from omental AT-conditioned media from normal glucose tolerant (NGT) pregnant women (n = 65) and pregnant women with GDM (n = 82). Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry was used to construct a small ion library from AT and exosomal proteins, followed by ingenuity pathway analysis to determine the canonical pathways and biofunctions. The effect of exosomes on human placental cells was determined using a Human Glucose Metabolism RT2 Profiler PCR array.

RESULTS

The number of exosomes (vesicles/μg of tissue/24 hours) was substantially (1.7-fold) greater in GDM than in NGT, and the number of exosomes correlated positively with the birthweight Z score. Ingenuity pathway analysis of the exosomal proteins revealed differential expression of the proteins targeting the sirtuin signaling pathway, oxidative phosphorylation, and mechanistic target of rapamycin signaling pathway in GDM compared with NGT. GDM exo-AT increased the expression of genes associated with glycolysis and gluconeogenesis in placental cells compared with the effect of NGT exo-AT.

CONCLUSIONS

Our findings are consistent with the possibility that AT exosomes play an important role in mediating the changes in placental function in GDM and might be responsible for some of the adverse consequences in this pregnancy complication, such as fetal overgrowth.

Quantitative Proteomics by SWATH-MS of Maternal Plasma Exosomes Determine Pathways Associated With Term and Preterm Birth

Exosomes are membrane-bound nanovesicles that transport molecular signals between cells. This study determined changes in maternal plasma exosome proteomics contents in term and preterm births. Maternal plasma (MP) samples were collected from group 1: term not in labor (TNIL, n = 13); group 2: term in labor (TL, n = 11); group 3: preterm premature rupture of membranes (pPROM, n = 8); and group 4: preterm birth (PTB, n = 13). Exosomes isolated from plasma by differential density centrifugation followed by size exclusion chromatography were characterized by morphology (electron microscopy), quantity and size (nanoparticle tracking analysis), and markers (western blot). A quantitative, information-independent acquisition [sequential windowed acquisition of all theoretical mass spectra (SWATH-MS)] approach was used to determine the protein profile in exosomes. Ingenuity Pathway Analysis determined pathways associated with the protein profile identified in exosomes. MP exosomes were spherical, had a mean diameter of 120 nm, and were positive for exosomal proteins CD63 and TSG101 irrespective of pregnancy status. No distinct changes in exosome quantities were seen in maternal circulation across the groups. SWATH-MS identified 72 statistically significant proteins across the groups studied. Bioinformatics analysis showed the proteins within the exosomes in TNIL, TL, pPROM, and PTB target pathways mainly associated with inflammatory and metabolic signals. Exosomal data suggest that homeostatic imbalances, specifically inflammatory and endocrine signaling, might disrupt pregnancy maintenance resulting in labor-related changes both at term and preterm. Reflection of physiologic changes in exosomes is suggestive of its usefulness as biomarkers and cellular function indicators.

Circulating Exosomal miRNA Profile During Term and Preterm Birth Pregnancies: A Longitudinal Study

Despite decades of research in the field of human reproduction, the mechanisms responsible for human parturition still remain elusive. The objective of this study was to describe the changes in the exosomal miRNA concentrations circulating in the maternal plasma between mothers delivering term and preterm neonates, across gestation using a longitudinal study design. This descriptive study identifies the miRNA content in exosomes present in maternal plasma of term and preterm birth (PTB) (n = 20 and n = 10 per each gestational period, respectively) across gestation (i.e., first, second, and third trimesters and at the time of delivery). Changes in exosomal miRNA signature in maternal plasma during term and preterm gestation were determined using the NextSeq 500 high-output 75 cycles sequencing platform. A total of 167 and 153 miRNAs were found to significantly change (P < 0.05) as a function of the gestational age across term and PTB pregnancies, respectively. Interestingly, a comparison analysis between the exosomal miRNA profile between term and PTB reveals a total of 173 miRNAs that significantly change (P < 0.05) across gestation. Specific trends of changes (i.e., increase, decrease, and both) as a function of the gestational age were also identified. The bioinformatics analyses establish that the differences in the miRNA profile are targeting signaling pathways associated with TGF-β signaling, p53, and glucocorticoid receptor signaling, respectively. These data suggest that the miRNA content of circulating exosomes in maternal blood might represent a biomolecular "fingerprint" of the progression of pregnancy.

The potential role of miRNAs and exosomes in chemotherapy in ovarian cancer

Chemoresistance is one of the major obstacles in the treatment of cancer patients. It poses a fundamental challenge to the effectiveness of chemotherapy and is often linked to relapse in patients. Chemoresistant cells can be identified in different types of cancers; however, ovarian cancer has one of the highest rates of chemoresistance-related relapse (50% of patients within 5 years). Resistance in cells can either develop through prolonged cycles of treatment or through intrinsic pathways. Mechanistically, the problem of drug resistance is complex mainly because numerous factors are involved, such as overexpression of drug efflux pumps, drug inactivation, DNA repair mechanisms and alterations to and/or mutations in the drug target. Additionally, there is strong evidence that circulating miRNAs participate in the development of chemoresistance. Recently, miRNAs have been identified in exosomes, where they are encapsulated and hence protected from degradation. These miRNAs within exosomes (exo-miRNAs) can regulate the gene expression of target cells both locally and systemically. Exo-miRNAs play an important role in disease progression and can potentially facilitate chemoresistance in cancer cells. In addition, and from a diagnostic perspective, exo-miRNAs profiles may contribute to the development of predictive models to identify responder and non-responder chemotherapy. Such model may also be used for monitoring treatment response and disease progression. Exo-miRNAs may ultimately serve as both a predictive biomarker for cancer response to therapy and as a prognostic marker for the development of chemotherapy resistance. Therefore, this review examines the potential role of exo-miRNAs in chemotherapy in ovarian cancer.

Circulating cell-free miR-494 and miR-21 are disease response biomarkers associated with interim-positron emission tomography response in patients with diffuse large B-cell lymphoma

MicroRNA (miRNA)s are dysregulated in Diffuse large B-cell lymphoma (DLBCL), where they reflect the malignant B-cells and the immune infiltrate within the tumor microenvironment. There remains a paucity of data in DLBCL regarding cell-free (c-f) miRNA as disease response biomarkers. Immunosuppressive monocyte/macrophages, which are enriched in DLBCL, are disease response markers in DLBCL, with miRNA key regulators of their immunosuppressive function. Our aim was to determine whether plasma miRNA that reflect the activity of the malignant B-cell and/or immunosuppressive monocytes/macrophages, have value as minimally-invasive disease response biomarkers in DLBCL.

Quantification of 99 DLBCL tissues, to select miRNA implicated in immunosuppressive monocytes/macrophage biology, found miR-494 differentially elevated. In a discovery cohort (22 patients), pre-therapy c-f miR-494 and miR-21 but not miR-155 were raised relative to healthy plasma. Both miR-494 and miR-21 levels 3-6 months reduced post immuno-chemotherapy. The validation cohort (56 patients) was from a prospective clinical trial. Interestingly, in sequential samples both miRNAs decreased in patients becoming Positron Emission Tomography/Computerized Tomography (PET/CT)-ve, but not in those remaining interim-PET/CT+. Patient monocytes were phenotypically and functionally immunosuppressive with ex-vivo monocyte depletion enhancing T-cell proliferation in patient but not healthy samples. Pre-therapy monocytes showed an immunosuppressive transcriptome and raised levels of miR-494. MiR-494 was present in all c-f nanoparticle fractions but was most readily detectable in unfractionated plasma.

Circulating c-f miR-494 and miR-21 are disease response biomarkers with differential response stratified by interim-PET/CT in patients with DLBCL. Further studies are required to explore their manipulation as potential therapeutic targets.

Differential Expression of Keratinocyte-Derived Extracellular Vesicle Mirnas Discriminate Exosomes From Apoptotic Bodies and Microvesicles

Extracellular vesicles (EVs) are mammalian cell-derived nano-scale structures enclosed by a lipid bilayer that were previously considered to be cell debris with little biological value. However, EVs are now recognized to possess biological function, acting as a packaging, transport and delivery mechanisms by which functional molecules (i.e., miRNAs) can be transferred to target cells over some distance. To examine the miRNA from keratinocyte-derived EVs, we isolated three distinct populations of EVs from both HaCaT and primary human keratinocytes (PKCs) and characterized their biophysical, biochemical and functional features by using microscopy, immunoblotting, nanoparticle tracking, and next generation sequencing. We identified 1,048; 906; and 704 miRNAs, respectively, in apoptotic bodies (APs), microvesicles (MVs) and exosomes (EXs) released from HaCaT, and 608; 506; and 622 miRNAs in APs, MVs and EXs released from PKCs. In which, there were 623 and 437 identified miRNAs common to three HaCaT-derived EVs and PKC-derived EVs, respectively. In addition, we found hundreds of exosomal miRNAs that were previously un-reported. Differences in the abundance levels of the identified EV miRNAs could discriminate between the three EV populations. These data contribute substantially to knowledge within the EV-identified miRNA database, especially with regard to keratinocyte-derived EV miRNA content.

Amniotic Fluid Exosome Proteomic Profile Exhibits Unique Pathways of Term and Preterm Labor

Our objective was to determine the amniotic fluid-derived exosomal proteomic profile in patients who had spontaneous preterm birth (PTB) or preterm premature rupture of membranes (pPROM) compared with those who delivered at term. A cross-sectional study of a retrospective cohort was used to quantify and determine the protein content of exosomes present in amniotic fluid, in PTB or pPROM, and normal term labor (TL) or term not in labor (TNIL) pregnancies. Exosomes were isolated by differential centrifugation and quantified using nanocrystals (Qdot) coupled to CD63 and placental alkaline phosphatase (PLAP) by fluorescence nanoparticle tracking analysis. The exosomal proteomic profile was identified by liquid chromatography-tandem mass spectrometry, and a small ion library was constructed to quantify the proteomic data by Sequential Window Acquisition of All Theoretical analysis. Ingenuity Pathway Analysis determined canonical pathways and biofunctions associated with dysregulated proteins. Amniotic fluid exosomes have similar shape and quantity regardless of the conditions; however, the PLAP/CD63 ratios for TL, PTB, and pPROM were significantly higher (∼3.8-, ∼4.4-, and ∼3.5-fold, respectively) compared with TNIL. The PLAP/CD63 ratio was also significantly higher (∼1.3-fold) in PTB compared with pPROM. Biological functions primarily indicated nonspecific inflammatory response regardless of condition, but unique profiles were also identified in cases (PTB and pPROM) compared with term. Amniotic fluid exosomes provide information specific to normal and abnormal parturition. Inflammatory marker enrichment and its uniqueness in term and preterm pregnancies support the value of exosomes in determining underlying physiology associated with term and preterm parturition.

Exosomal miRNA signature of pancreatic cyst: Liquid biopsies as indicators of pancreatic cancer

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Background: Pancreatic cysts are a group of lesions with malignant potential. Currently, there are no consistently reliable biomarkers or imaging modalities to accurately predict biologic behavior of these cysts. We tested the hypothesis that tumor-derived exosomes (better conserved than free miRNA) can be acquired endoscopically from pancreatic cyst fluid and may allow for improved distinction between benign, premalignant and malignant cysts. Methods: Exosomes were isolated and characterised by differential and buoyant centrifugation from pancreatic cyst fluid obtained from 30 patients with pseudocysts (PS), serous cystic (SC), mucinous cysts (MC), intraductal papillary mucinous neoplasms (IPMN), pancreatitis (PA), and pancreatic cancer (PC) , confirmed with imaging and histology. An Illumina TruSeq Small RNA kit was used to construct a small RNA library, and the libraries were sequenced using the Illumina NextSeq 500 platform. The resulting sequencing FASTQ files were analyzed using miRDeep2 to identify both known and novel miRNAs. Results: Four significant miRNAs which are shared between six of the analyses, specifically hsa-miR-199b-3p, hsa-miR-199a-2-3p, hsa-miR-199a-1-3p and hsa-let-7i-5p were identified. MiRNA hsa-miR-27a-3p was significant and shared between five of the analyses. A total of 15, 12 and 2 significant miRNAs were shared between four, three and two of the analyses, respectively. Importantly, there were a total of 10 significant miRNAs which were unique to each analysis, with the exception of IPMN vs Pseudocyst, and Pancreatic cancer vs Pancreatitis. Specifically these unique miRNAs for each analysis are: hsa-miR-92a-2-3p (Pancreatitis vs Pseudocyst); hsa-miR-92a-1-3p (Serous vs Pseudocyst); hsa-miR-30e-5p (Pancreatic cancer vs Serous), hsa-miR-30b-5p (IPMN vs Pancreatic cancer); and hsa-miR-23b-3p, hsa-miR-99b-5p, hsa-miR-222-3p, hsa-miR-31-5p, hsa-miR-151a-5p, hsa-miR-221-3p (Pancreatic cancer vs. Pseudocyst). Conclusions: Exosomal miRNAs in pancreatic fluid may be used as a biomarker to differentiate between various cyst types and pancreatic cancer. A larger cohort with miRNA quantification and is needed to further validate these findings .

Using a Next-Generation Sequencing Approach to Profile MicroRNAs from Human Origin

Next-generation sequencing is a powerful method to interrogate the nucleotide composition for millions of DNA strands simultaneously. This technology can be utilized to profile microRNAs from multiple origins, such as tissues, cells, and body fluids. Next-generation sequencing is increasingly becoming a common and readily available technique for all laboratories. However, the bottleneck for next-generation sequencing is not within the laboratory but with the bioinformatics and data analysis of next-generation sequencing data. This chapter briefly describes the methods used to prepare samples for next-generation sequencing within the laboratory, before a deeper description of the methods used for data analysis.

Placental Exosomes as Early Biomarker of Preeclampsia: Potential Role of Exosomal MicroRNAs Across Gestation

CONTEXT

There is a need to develop strategies for early prediction of patients who will develop preeclampsia (PE) to establish preventive strategies to reduce the prevalence and severity of the disease and their associated complications.

OBJECTIVE

The objective of this study was to investigate whether exosomes and their microRNA cargo present in maternal circulation can be used as early biomarker for PE.

DESIGN, SETTING, PATIENTS, AND INTERVENTIONS

A retrospective stratified study design was used to quantify total exosomes and placenta-derived exosomes present in maternal plasma of normal (n = 32 per time point) and PE (n = 15 per time point) pregnancies. Exosomes present in maternal circulation were determined by nanoparticle tracking analysis. An Illumina TruSeq® Small RNA Library Prep Kit was used to construct a small RNA library from exosomal RNA obtained from plasma samples.

RESULTS

In presymptomatic women, who subsequently developed PE, the concentration of total exosomes and placenta-derived exosomes in maternal plasma was significantly greater than those observed in controls, throughout pregnancy. The area under the receiver operating characteristic curves for total exosome and placenta-derived exosome concentrations were 0.745 ± 0.094 and 0.829 ± 0.077, respectively. In total, over 300 microRNAs were identified in exosomes across gestation, where hsa-miR-486-1-5p and hsa-miR-486-2-5p were identified as the candidate microRNAs.

CONCLUSIONS

Although the role of exosomes during PE remains to be fully elucidated, we suggest that the concentration and content of exosomes may be of diagnostic utility for women at risk for developing PE.

Oxygen tension regulates the miRNA profile and bioactivity of exosomes released from extravillous trophoblast cells - Liquid biopsies for monitoring complications of pregnancy

Our understanding of how cells communicate has undergone a paradigm shift since the recent recognition of the role of exosomes in intercellular signaling. In this study, we investigated whether oxygen tension alters the exosome release and miRNA profile from extravillous trophoblast (EVT) cells, modifying their bioactivity on endothelial cells (EC). Furthermore, we have established the exosomal miRNA profile at early gestation in women who develop pre-eclampsia (PE) and spontaneous preterm birth (SPTB). HTR-8/SVneo cells were used as an EVT model. The effect of oxygen tension (i.e. 8% and 1% oxygen) on exosome release was quantified using nanocrystals (Qdot®) coupled to CD63 by fluorescence NTA. A real-time, live-cell imaging system (Incucyte™) was used to establish the effect of exosomes on EC. Plasma samples were obtained at early gestation (<18 weeks) and classified according to pregnancy outcomes. An Illumina TrueSeq Small RNA kit was used to construct a small RNA library from exosomal RNA obtained from EVT and plasma samples. The number of exosomes was significantly higher in EVT cultured under 1% compared to 8% oxygen. In total, 741 miRNA were identified in exosomes from EVT. Bioinformatic analysis revealed that these miRNA were associated with cell migration and cytokine production. Interestingly, exosomes isolated from EVT cultured at 8% oxygen increased EC migration, whilst exosomes cultured at 1% oxygen decreased EC migration. These changes were inversely proportional to TNF-α released from EC. Finally, we have identified a set of unique miRNAs in exosomes from EVT cultured at 1% oxygen and exosomes isolated from the circulation of mothers at early gestation, who later developed PE and SPTB. We suggest that aberrant exosomal signalling by placental cells is a common aetiological factor in pregnancy complications characterised by incomplete SpA remodeling and is therefore a clinically relevant biomarker of pregnancy complications.

Review: Bio-compartmentalization of microRNAs in exosomes during gestational diabetes mellitus

Analysis of the human genome revealed that only 1.2% encoded for proteins, which raised questions regarding the biological significance of the remaining genome. We now know that approximately 80% of the genome serves at least one biochemical function within the cell. A portion of this 80% consists of a family of non-coding regulatory RNAs, one important member being microRNAs (miRNAs). miRNAs can be detected in tissues and biofluids, where miRNAs in the latter can be bound to proteins or encapsulated within lipid vesicles such as exosomes. Gestational diabetes mellitus (GDM) is a complication of pregnancy, which has harmful health impacts on both the fetus as well as the mother. The incidence of GDM worldwide varies, but reached 18% in the HAPO cohort using the new International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria. Not only has GDM been associated with increased risks of further complications during pregnancy, but also poses long-term risks for both the mother and the baby. Thus, understanding the pathophysiology of GDM is important from a public health perspective. Literature has demonstrated that GDM is associated with elevated levels of circulating exosomes in maternal circulation. However, there is a paucity of data defining the expression, role, and diagnostic utility of miRNAs in GDM. This review briefly summarizes recent advances in the function and quantification of intracellular and extracellular miRNAs in GDM.

Abstract 4379: Exosomes isolated from ovarian cancer cells transfer oncogenic features to the target cells promoting epithelial to mesenchymal transition

Introduction: Recent studies establish the role of exosomes in cell-cell communication in cancer. As adaptation to hypoxia is a critical step in tumor progression, the aim of this study was to test the hypotheses that hypoxia promotes epithelial to mesenchymal transition (EMT) and that exosomes isolated from hypoxic cancer cells transfer oncogenic properties to target cells.

Methods: CaOV-3 cell line was used as model of ovarian cancer. Cells were cultured under 8% O2 (normoxia) and 1% O2 (hypoxia) for 48 hours. Exosomes were isolated from cell-conditioned media by differential and buoyant density centrifugation. Exosomes were characterised by the presence of TSG101 using Western Blot, size distribution (Nanosight™) and morphology by electron microscopy. Exosomal protein and miRNA content were determined using liquid chromatography mass spectrometry (5600 Triple TOF, AB Sciex,) and an Illumina NextSeq 500 Platform, respectively. The effects of exosomes released from CaOV-3 incubated under 1% O2 on EMT induction in CaOV-3 cells cultured under 8% O2 were assessed by the measuring the ratio of E-cadherin (epithelial marker) to N-cadherin (mesenchymal marker) by Wester Blot and the expression of 84 key genes involve in the EMT (RT2 Profiler™ PCR Array, QIAGEN).

Results: Exosomes were identified as spherical vesicles with a typical cup-shape, diameters ranging from 50 to 100 nm with the expression of TSG101. Exosome release from ovarian cancer cells was ∼4-fold higher under hypoxic than normoxic conditions (p &lt;0.001). Hypoxia-specific exosomal proteins and miRNAs were identified. Hypoxia induced EMT (increased N-cadherin/E-cadherin ratio) on CaOV-3 cells compared to cells cultured under 8% O2. Interestingly, exosomes isolated from hypoxic conditions mimic the effect of hypoxia on cells cultured under 8% O2, involving the unregulated of a set of transcription factors associated with EMT such as SNAIL1/SNAIL2, bHLH (E47, E2-2, and TWIST1/TWIST2), and ZEB1/ZEB2.

Conclusion: The data obtained is consistent with the hypothesis that exosomes released from cancer cells modify the phenotype of target cells by transferring pro-oncogenic molecules inducing cancerous phenotype of receipt cells, contributing to tumour growth and metastasis.

Citation Format: Miharu Kobayashi, Laura Cohelo, Dominic Guanzon, Katherin Scholz-Romero, Melissa Brown, Richard Kline, Li Li, Gregory Rice, Carlos Salomon. Exosomes isolated from ovarian cancer cells transfer oncogenic features to the target cells promoting epithelial to mesenchymal transition. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4379.