VCD-induced menopause mouse model reveals reprogramming of hepatic metabolism

OBJECTIVE

Menopause adversely impacts systemic energy metabolism and increases the risk of metabolic disease(s) including hepatic steatosis, but the mechanisms are largely unknown. Dosing female mice with vinyl cyclohexene dioxide (VCD) selectively causes follicular atresia in ovaries, leading to a murine menopause-like phenotype.

METHODS

In this study, we treated female C57BL6/J mice with VCD (160 mg/kg i.p. for 20 consecutive days followed by verification of the lack of estrous cycling) to investigate changes in body composition, energy expenditure (EE), hepatic mitochondrial function, and hepatic steatosis across different dietary conditions.

RESULTS

VCD treatment induced ovarian follicular loss and increased follicle-stimulating hormone (FSH) levels in female mice, mimicking a menopause-like phenotype. VCD treatment did not affect body composition, or EE in mice on a low-fat diet (LFD) or in response to a short-term (1-week) high-fat, high sucrose diet (HFHS). However, the transition to a HFHS lowered cage activity in VCD mice. A chronic HFHS diet (16 weeks) significantly increased weight gain, fat mass, and hepatic steatosis in VCD-treated mice compared to HFHS-fed controls. In the liver, VCD mice showed suppressed hepatic mitochondrial respiration on LFD, while chronic HFHS resulted in compensatory increases in hepatic mitochondrial respiration. Also, liver RNA sequencing revealed that VCD promoted global upregulation of hepatic lipid/cholesterol synthesis pathways.

CONCLUSION

Our findings suggest that the VCD-induced menopause model compromises hepatic mitochondrial function and lipid/cholesterol homeostasis that sets the stage for HFHS diet-induced steatosis while also increasing susceptibility to obesity.

Sexual dimorphism during integrative endocrine and immune responses to ionizing radiation in mice

Exposure to cosmic ionizing radiation is an innate risk of the spaceflight environment that can cause DNA damage and altered cellular function. In astronauts, longitudinal monitoring of physiological systems and interactions between these systems are important to consider for mitigation strategies. In addition, assessments of sex-specific biological responses in the unique environment of spaceflight are vital to support future exploration missions that include both females and males. Here we assessed sex-specific, multi-system immune and endocrine responses to simulated cosmic radiation. For this, 24-week-old, male and female C57Bl/6J mice were exposed to simplified five-ion, space-relevant galactic cosmic ray (GCRsim) radiation at 15 and 50 cGy, to simulate predicted radiation exposures that would be experienced during lunar and Martian missions, respectively. Blood and adrenal tissues were collected at 3- and 14-days post-irradiation for analysis of immune and endocrine biosignatures and pathways. Sexually dimorphic adrenal gland weights and morphology, differential total RNA expression with corresponding gene ontology, and unique immune phenotypes were altered by GCRsim. In brief, this study offers new insights into sexually dimorphic immune and endocrine kinetics following simulated cosmic radiation exposure and highlights the necessity for personalized translational approaches for astronauts during exploration missions.

LH/hCG Regulation of Circular RNA in Mural Granulosa Cells during the Periovulatory Period in Mice

Ovarian follicles undergo a series of dynamic changes following the ovulatory surge of luteinizing hormone including cumulus expansion, oocyte maturation, ovulation, and luteinization. Post-transcriptional gene regulatory events are critical for mediating LH follicular responses, and among all RNA isoforms, circular RNA (circRNA) is one of the most abundant forms present in cells, yet they remain the least studied. Functionally, circRNA can act as miRNA sponges, protein sponges/decoys, and regulators of transcription and translation. In the context of ovarian follicular development, the identity and roles of circRNA are relatively unknown. In the present study, high throughput RNA sequencing of granulosa cells immediately prior to and 4-h after the LH/hCG surge identified 42,381 circRNA originating from 7712 genes. A total of 54 circRNA were identified as differentially expressed between 0-h and 4-h time points (Fold Change ± 1.5, FDR ≤ 0.1), among them 42 circRNA were upregulated and 12 circRNA were downregulated. All differentially expressed circRNA between the 0-h and 4-h groups were subjected to circinteractome analysis and identified networks of circRNA-protein and circRNA-miRNA were further subjected to "micro-RNA target filter analysis" in Ingenuity Pathway Analyses, which resulted in the identification of miRNA targeted mRNAs. A comparison of these circRNA target mRNAs with LH-induced mRNAs identified Runx2, Egfr, Areg, Sult1el, Cyp19a1, Cyp11a1, and Hsd17b1 as targets of circKif2, circVcan, circMast4, and circMIIt10. These newly identified LH/hCG-induced circRNA, their target miRNA and protein networks provide new insights into the complex interactions associated with periovulatory follicular development.

Exomap1 mouse: a transgenic model for in vivo studies of exosome biology

Exosomes are small extracellular vesicles (sEVs) of ~30-150 nm in diameter that have the same topology as the cell, are enriched in selected exosome cargo proteins, and play important roles in health and disease. To address large unanswered questions regarding exosome biology in vivo, we created the exomap1 transgenic mouse model. In response to Cre recombinase, exomap1 mice express HsCD81mNG, a fusion protein between human CD81, the most highly enriched exosome protein yet described, and the bright green fluorescent protein mNeonGreen. As expected, cell type-specific expression of Cre induced the cell type-specific expression of HsCD81mNG in diverse cell types, correctly localized HsCD81mNG to the plasma membrane, and selectively loaded HsCD81mNG into secreted vesicles that have the size (~80 nm), topology (outside out), and content (presence of mouse exosome markers) of exosomes. Furthermore, mouse cells expressing HsCD81mNG released HsCD81mNG-marked exosomes into blood and other biofluids. Using high-resolution, single-exosome analysis by quantitative single molecule localization microscopy, we show here that that hepatocytes contribute ~15% of the blood exosome population whereas neurons contribute <1% of blood exosomes. These estimates of cell type-specific contributions to blood EV population are consistent with the porosity of liver sinusoidal endothelial cells to particles of ~50-300 nm in diameter, as well as with the impermeability of blood-brain and blood-neuron barriers to particles >5 nm in size. Taken together, these results establish the exomap1 mouse as a useful tool for in vivo studies of exosome biology, and for mapping cell type-specific contributions to biofluid exosome populations. In addition, our data confirm that CD81 is a highly-specific marker for exosomes and is not enriched in the larger microvesicle class of EVs.

Procoagulant Activity of Umbilical Cord-Derived Mesenchymal Stromal Cells' Extracellular Vesicles (MSC-EVs)

Many cell types, including cancer cells, release tissue factor (TF)-exposing extracellular vesicles (EVs). It is unknown whether MSC-EVs pose a thromboembolism risk due to TF expression. Knowing that MSCs express TF and are procoagulant, we hypothesize that MSC-EVs also might. Here, we examined the expression of TF and the procoagulant activity of MSC-EVs and the impact of EV isolation methods and cell culture expansion on EV yield, characterization, and potential risk using a design of experiments methodology. MSC-EVs were found to express TF and have procoagulant activity. Thus, when MSC-derived EVs are employed as a therapeutic agent, one might consider TF, procoagulant activity, and thromboembolism risk and take steps to prevent them.

Changes in cortical endoplasmic reticulum clusters in the fertilized mouse oocyte†

Oocytes from many invertebrate and vertebrate species exhibit unique endoplasmic reticulum (ER) specializations (cortical ER clusters), which are thought to be essential for egg activation. In examination of cortical ER clusters, we observed that they were tethered to previously unreported fenestrae within the cortical actin layer. Furthermore, studies demonstrated that sperm preferentially bind to the plasma membrane overlying the fenestrae, establishing close proximity to underlying ER clusters. Moreover, following sperm-oocyte fusion, cortical ER clusters undergo a previously unrecognized global change in volume and shape that persists through sperm incorporation, before dispersing at the pronuclear stage. These changes did not occur in oocytes from females mated with Izumo1 -/- males. In addition to these global changes, highly localized ER modifications were noted at the sperm binding site as cortical ER clusters surround the sperm head during incorporation, then form a diffuse cloud surrounding the decondensing sperm nucleus. This study provides the first evidence that cortical ER clusters interact with the fertilizing sperm, indirectly through a previous unknown lattice work of actin fenestrae, and then directly during sperm incorporation. These observations raise the possibility that oocyte ER cluster-sperm interactions provide a competitive advantage to the oocyte, which may not occur during assisted reproductive technologies such as intracytoplasmic sperm injection.

Effect of Pre-Processing Storage Condition of Cell Culture-Conditioned Medium on Extracellular Vesicles Derived from Human Umbilical Cord-Derived Mesenchymal Stromal Cells

EVs can be isolated from a conditioned medium derived from mesenchymal stromal cells (MSCs), yet the effect of the pre-processing storage condition of the cell culture-conditioned medium prior to EV isolation is not well-understood. Since MSCs are already in clinical trials, the GMP-grade of the medium which is derived from their manufacturing might have the utility for preclinical testing, and perhaps, for clinical translation, so the impact of pre-processing storage condition on EV isolation is a barrier for utilization of this MSC manufacturing by-product. To address this problem, the effects of the pre-processing storage conditions on EV isolation, characterization, and function were assessed using a conditioned medium (CM) derived from human umbilical cord-derived MSCs (HUC-MSCs). Hypothesis: The comparison of three different pre-processing storage conditions of CM immediately processed for EV isolation would reveal differences in EVs, and thus, suggest an optimal pre-processing storage condition. The results showed that EVs derived from a CM stored at room temperature, 4 °C, −20 °C, and −80 °C for at least one week were not grossly different from EVs isolated from the CM immediately after collection. EVs derived from an in pre-processing −80 °C storage condition had a significantly reduced polydispersity index, and significantly enhanced dot blot staining, but their zeta potential, hydrodynamic size, morphology and size in transmission electron microscopy were not significantly different from EVs derived from the CM immediately processed for isolation. There was no impact of pre-processing storage condition on the proliferation of sarcoma cell lines exposed to EVs. These data suggest that the CM produced during GMP-manufacturing of MSCs for clinical applications might be stored at −80 °C prior to EV isolation, and this may enable production scale-up, and thus, and enable preclinical and clinical testing, and EV lot qualification.

Heat-induced increases in body temperature in lactating dairy cows: impact on the cumulus and granulosa cell transcriptome of the periovulatory follicle

Cows acutely heat stressed after a pharmacologically induced luteinizing hormone (LH) surge had periovulatory changes in the follicular fluid proteome that may potentiate ovulation and impact oocyte developmental competence. Because the cellular origins of differentially abundant proteins were not known, we have examined the cumulus and granulosa cell transcriptomes from the periovulatory follicle in cows exhibiting varying levels of hyperthermia when occurring after the LH surge. After pharmacological induction of a dominant follicle, lactating dairy cows were administered gonadotropin releasing hormone (GnRH) and maintained in thermoneutral conditions (~67 temperature-humidity index [THI]) or heat stress conditions where THI was steadily increased for ~12 h (71 to 86 THI) and was sufficient to steadily elevate rectal temperatures. Cumulus-oocyte complexes and mural granulosa cells were recovered by transvaginal aspiration of dominant follicle content ~16 h after GnRH. Rectal temperature was used as a continuous, independent variable to identify differentially expressed genes (DEGs) increased or decreased per each 1 °C change in temperature. Cumulus (n = 9 samples) and granulosa (n = 8 samples) cells differentially expressed (false discovery rate [FDR] < 0.05) 25 and 87 genes, respectively. The majority of DEGs were upregulated by hyperthermia. Steady increases in THI are more like the "turning of a dial" than the "flipping of a switch." The moderate but impactful increases in rectal temperature induced modest fold changes in gene expression (<2-fold per 1 °C change in rectal temperature). Identification of cumulus DEGs involved in cell junctions, plasma membrane rafts, and cell-cycle regulation are consistent with marked changes in the interconnectedness and function of cumulus after the LH surge. Depending on the extent to which impacts may be occurring at the junctional level, cumulus changes may have indirect but impactful consequences on the oocyte as it undergoes meiotic maturation. Two granulosa cell DEGs have been reported by others to promote ovulation. Based on what is known, several other DEGs are suggestive of impacts on collagen formation or angiogenesis. Collectively these and other findings provide important insight regarding the extent to which the transcriptomes of the components of the periovulatory follicle (cumulus and mural granulosa cells) are affected by varying degrees of hyperthermia.

Single-Particle Interferometric Reflectance Imaging Characterization of Individual Extracellular Vesicles and Population Dynamics

Extracellular vesicles (EVs) are nanometer-sized vesicles with a lipid bilayer that are secreted by most cells. EVs carry a multitude of different biological molecules, including protein, lipid, DNA, and RNA, and are postulated to facilitate cell-to-cell communication in diverse tissues and organs. Recently, EVs have attracted significant attention as biomarkers for diagnostics and therapeutic agents for various diseases. Many methods have been developed for EV characterization. However, current methods for EV analysis all have different limitations. Thus, developing efficient and effective methods for EV isolation and characterization remains one of the crucial steps for this cutting-edge research field as it matures. Here, we provide a detailed protocol outlining a single-particle interferometric reflectance imaging sensor (SP-IRIS), as a method that is capable of detecting and characterizing EVs from unpurified biological sources and purified EVs by other methodologies. This advanced technique can be used for multi-level and comprehensive measurements for the analysis of EV size, EV count, EV phenotype, and biomarker colocalization.

Improving Reproducibility to Meet Minimal Information for Studies of Extracellular Vesicles 2018 Guidelines in Nanoparticle Tracking Analysis

Nanoparticle tracking analysis (NTA) has been one of several characterization methods used for extracellular vesicle (EV) research since 2006. Many consider that NTA instruments and their software packages can be easily utilized following minimal training and that size calibration is feasible in-house. As both NTA acquisition and software analysis constitute EV characterization, they are addressed in Minimal Information for Studies of Extracellular Vesicles 2018 (MISEV2018). In addition, they have been monitored by Transparent Reporting and Centralizing Knowledge in Extracellular Vesicle Research (EV-TRACK) to improve the robustness of EV experiments (e.g., minimize experimental variation due to uncontrolled factors). Despite efforts to encourage the reporting of methods and controls, many published research papers fail to report critical settings needed to reproduce the original NTA observations. Few papers report the NTA characterization of negative controls or diluents, evidently assuming that commercially available products, such as phosphate-buffered saline or ultrapure distilled water, are particulate-free. Similarly, positive controls or size standards are seldom reported by researchers to verify particle sizing. The Stokes-Einstein equation incorporates sample viscosity and temperature variables to determine particle displacement. Reporting the stable laser chamber temperature during the entire sample video collection is, therefore, an essential control measure for accurate replication. The filtration of samples or diluents is also not routinely reported, and if so, the specifics of the filter (manufacturer, membrane material, pore size) and storage conditions are seldom included. The International Society for Extracellular Vesicle (ISEV)'s minimal standards of acceptable experimental detail should include a well-documented NTA protocol for the characterization of EVs. The following experiment provides evidence that an NTA analysis protocol needs to be established by the individual researcher and included in the methods of publications that use NTA characterization as one of the options to fulfill MISEV2018 requirements for single vesicle characterization.

Forkhead box F1 induces columnar phenotype and epithelial-to-mesenchymal transition in esophageal squamous cells to initiate Barrett's like metaplasia

Multiple genome-wide association studies (GWAS) have linked Forkhead Box F1 (FOXF1) to Barrett's esophagus (BE). Understanding whether FOXF1 is involved in initiation of Barrett's metaplasia could allow FOXF1 to be used for risk stratification and for therapy. Two-dimensional cell cultures and three-dimensional organoid cultures and well-annotated human biopsies were used to determine the role of FOXF1 in BE pathogenesis. Multiple established esophageal squamous and BE cell lines were tested in gain- and loss-of-function studies. Initiation of a BE-like metaplastic change was evaluated by measuring characteristic cytokeratins and global gene expression profiling and by culturing organoids. Epithelial-mesenchymal transition (EMT) was evaluated by immunostaining for E-cadherin, vimentin and Snail, and by cell motility assay. Columnar esophageal epithelium of BE patients exhibited higher expression of FOXF1 compared to normal squamous esophageal epithelium of GERD patients (P < 0.001). Acidic bile salts induced nuclear FOXF1 in esophageal squamous cells. FOXF1 overexpression in normal esophageal squamous cells: (a) increased columnar cytokeratins and decreased squamous cytokeratins, (b) converted squamous organoids to glandular organoids, and (c) switched global gene profiles to resemble that of human BE epithelium (P = 2.1685e - 06 for upregulated genes and P = 8.3378e - 09 for downregulated genes). FOXF1 inhibition in BE cell lines led to loss of BE differentiation markers, CK7, and mucin 2. Also, FOXF1 induced EMT and promoted cell motility in normal esophageal squamous epithelial cells. FOXF1-induced genes mapped to pathways such as Cancer, Cellular Assembly and Organization, DNA Replication, Recombination, and Repair. In conclusion, FOXF1 promotes a BE-like columnar phenotype and cell motility in esophageal squamous epithelial cells, which may have a critical role in BE development. FOXF1 should be studied further as a biomarker for BE and as a target for BE treatment.

Granulosa cell genes that regulate ovarian follicle development beyond the antral stage: The role of estrogen receptor β

Follicle development beyond the preantral stage is dependent on gonadotropins. FSH signaling is crucial for the advancement of preantral follicles to the antral stage, and LH signaling is essential for further maturation of preovulatory follicles. Estrogen is intricately tied to gonadotropin signaling during the advanced stages of folliculogenesis. We observed that Erβ^null ovarian follicles fail to develop beyond the antral stage, even after exogenous gonadotropin stimulation. As ERβ is primarily expressed in the granulosa cells (GCs), we explored the gonadotropin-regulated GC genes that induce maturation of antral follicles. Synchronized follicle development was induced by administration of exogenous gonadotropins to wildtype 4-wk-old female rats. The GC transcriptome was analyzed via RNA-sequencing before and after gonadotropin stimulation. An Erβ^null mutant model that fails to show follicle maturation was also included in order to identify the ERβ-regulated genes involved at this step. We observed that specific groups of genes were differentially expressed in response to PMSG or hCG administration in wildtype rats. While some of the PMSG or hCG-induced genes showed a similar expression pattern in Erβ^null GCs, a subset of PMSG- or hCG-induced genes showed a differential expression pattern in Erβ^null GCs. These latter ERβ-regulated genes included previously known FSH or LH target genes including Lhcgr, Cyp11a1, Cyp19a1, Pgr, Runx2, Egfr, Kiss1, and Ptgs2, which are involved in follicle development, oocyte maturation, and ovulation. We also identified novel ERβ-regulated genes including Jaml, Galnt6, Znf750, Dusp9, Wnt16, and Mageb16 that failed to respond to gonadotropin stimulation in Erβ^null GCs. Our findings indicate that the gonadotropin-induced spatiotemporal pattern of gene expression is essential for ovarian follicle maturation beyond the antral stage. However, expression of a subset of those gonadotropin-induced genes is dependent on transcriptional regulation by ERβ.

Modulation of Immune Response to Chlamydia muridarum by Host miR-135a

Previously, our laboratory established the role of small, noncoding RNA species, i.e., microRNA (miRNA) including miR-135a in anti-chlamydial immunity in infected hosts. We report here chlamydial infection results in decreased miR-135a expression in mouse genital tissue and a fibroblast cell line. Several chemokine and chemokine receptor genes (including CXCL10, CCR5) associated with chlamydial pathogenesis were identified in silico to contain putative miR-135a binding sequence(s) in the 3' untranslated region. The role of miR-135a in the host immune response was investigated using exogenous miR-135a mimic to restore the immune phenotype associated with decreased miR-135a following Chlamydia muridarum (Cm) infection. We observed miR-135a regulation of Cm-primed bone marrow derived dendritic cells (BMDC) via activation of Cm-immune CD4⁺ T cells for clonal expansion and CCR5 expression. Using a transwell cell migration assay, we explore the role of miR-135a in regulation of genital tract CXCL10 expression and recruitment of CXCR3⁺ CD4⁺ T cells via the CXCL10/CXCR3 axis. Collectively, data reported here support miR-135a affecting multiple cellular processes in response to chlamydial infection.

The RNA binding protein FMR1 controls selective exosomal miRNA cargo loading during inflammation

Cells respond to inflammatory disease states by releasing exosomes containing highly specific protein and RNA cargos, but how inflammation alters cargo specificity and secretion of exosomes is unknown. We show that increases in exosome secretion induced by either viral infection or LPS/ATP exposure result from inflammasome activation and subsequent caspase-1–dependent cleavage of the trafficking adaptor protein RILP. This cleaved form of RILP promotes the movement of multivesicular bodies toward the cell periphery and induces selective exosomal miRNA cargo loading. We have identified a common short sequence motif present in miRNAs that are selectively loaded into exosomes after RILP cleavage. This motif binds the RNA binding protein FMR1 and directs miRNA loading into exosomes via interaction with components of the ESCRT (endosomal sorting complex required for transport) pathway. These results indicate that inflammasome-mediated RILP cleavage, and sequence-specific interactions between miRNAs and FMR1, play a significant role in exosome cargo loading and enhanced secretion during cellular inflammatory responses.

Effects of spaceflight aboard the International Space Station on mouse estrous cycle and ovarian gene expression

Ovarian steroids dramatically impact normal homeostatic and metabolic processes of most tissues within the body, including muscle, bone, neural, immune, cardiovascular, and reproductive systems. Determining the effects of spaceflight on the ovary and estrous cycle is, therefore, critical to our understanding of all spaceflight experiments using female mice. Adult female mice (n = 10) were exposed to and sacrificed on-orbit after 37 days of spaceflight in microgravity. Contemporary control (preflight baseline, vivarium, and habitat; n = 10/group) groups were maintained at the Kennedy Space Center, prior to sacrifice and similar tissue collection at the NASA Ames Research Center. Ovarian tissues were collected and processed for RNA and steroid analyses at initial carcass thaw. Vaginal wall tissue collected from twice frozen/thawed carcasses was fixed for estrous cycle stage determinations. The proportion of animals in each phase of the estrous cycle (i.e., proestrus, estrus, metestrus, and diestrus) did not appreciably differ between baseline, vivarium, and flight mice, while habitat control mice exhibited greater numbers in diestrus. Ovarian tissue steroid concentrations indicated no differences in estradiol across groups, while progesterone levels were lower (p < 0.05) in habitat and flight compared to baseline females. Genes involved in ovarian steroidogenic function were not differentially expressed across groups. As ovarian estrogen can dramatically impact multiple non-reproductive tissues, these data support vaginal wall estrous cycle classification of all female mice flown in space. Additionally, since females exposed to long-term spaceflight were observed at different estrous cycle stages, this indicates females are likely undergoing ovarian cyclicity and may yet be fertile.

Inosine RNA modifications are enriched at the codon wobble position in mouse oocytes and eggs†

Mammalian oocytes and eggs are transcriptionally quiescent and depend on post-transcriptional mechanisms for proper maturation. Post-transcriptional mRNA modifications comprise an important regulatory mechanism that can alter protein and miRNA recognition sites, splicing, stability, secondary structure, and protein coding. We discovered that fully grown mouse germinal vesicle oocytes and metaphase II eggs display abundant inosine mRNA modifications compared to growing oocytes from postnatal day 12 oocytes. These inosines were enriched in mRNA protein coding regions (CDS) and specifically located at the third codon base, or wobble position. Inosines, observed at lower frequencies in CDS of somatic tissues, were similarly enriched at the codon wobble position. In oocytes and eggs, inosine modifications lead primarily to synonymous changes in mRNA transcripts. Inosines may ultimately affect maternal mRNA stability by changing codon usage, thereby altering translational efficiency and translationally coupled mRNA degradation. These important observations advance our understanding of post-transcriptional mechanisms contributing to mammalian oocyte maturation.

miRNA Profiling Reveals miRNA-130b-3p Mediates DENND1A Variant 2 Expression and Androgen Biosynthesis

Polycystic ovary syndrome (PCOS) is a common endocrine disorder of reproductive-age women involving overproduction of ovarian androgens and, in some cases, from the adrenal cortex. Family studies have established that PCOS is a complex heritable disorder with genetic and epigenetic components. Several small, noncoding RNAs (miRNAs) have been shown to be differentially expressed in ovarian cells and follicular fluid and in the circulation of women with PCOS. However, there are no reports of global miRNA expression and target gene analyses in ovarian theca cells isolated from normal cycling women and women with PCOS, which are key to the elucidation of the basis for the hyperandrogenemia characteristic of PCOS. With the use of small RNA deep sequencing (miR-seq), we identified 18 differentially expressed miRNAs in PCOS theca cells; of these, miR-130b-3p was predicted to target one of the PCOS genome-wide association study candidates, differentially expressed in neoplastic vs normal cells domain containing 1A (DENND1A). We previously reported that DENND1A variant 2 (DENND1A.V2), a truncated isoform of DENND1A, is upregulated in PCOS theca cells and mediates augmented androgen biosynthesis in PCOS theca cells. The comparison of miR-130b-3p in normal and PCOS theca cells demonstrated decreased miR-130b-3p expression in PCOS theca cells, which was correlated with increased DENND1A.V2, cytochrome P450 17α-hydroxylase (CYP17A1) mRNA and androgen biosynthesis. miR-130b-3p mimic studies established that increased miR130b-3p is correlated with decreased DENND1A.V2 and CYP17A1 expression. Thus, in addition to genetic factors, post-transcriptional regulatory mechanisms via miR-130b-3p underly androgen excess in PCOS. Ingenuity® Pathway Analysis Core Pathway and Network Analyses suggest a network by which miR-130b-3p, DENND1A, the luteinizing hormone/choriogonadotropin receptor, Ras-related protein 5B, and signaling pathways that they potentially target may mediate hyperandrogenism in PCOS.

Autoimmune Regulator is required in female mice for optimal embryonic development and implantation†

Autoimmune Regulator (AIRE) regulates central immune tolerance by inducing expression of tissue-restricted antigens in thymic medullary epithelial cells, thereby ensuring elimination of autoreactive T cells. Aire mutations in humans and targeted Aire deletion in mice result in multiorgan autoimmune disease, known in humans as autoimmune polyglandular syndrome type 1 (APS-1). APS-1 is characterized by the presence of adrenal insufficiency, chronic mucosal candidiasis, and/or hypoparathyroidism. Additionally, females often present with gonadal insufficiency and infertility. Aire-deficiency (KO) in mice results in oophoritis and age-dependent depletion of follicular reserves. Here, we found that while the majority of young 6-week-old Aire-KO females had normal follicular reserves, mating behavior, and ovulation rates, 50% of females experienced embryonic loss between gestation day (GD) 5.5 and 7.5 that could not be attributed to insufficient progesterone production or decidualization. The quality of GD0.5 embryos recovered from Aire KO mice was reduced, and when cultured in vitro, embryos displayed limited developmental capacity in comparison to those recovered from wild-type (WT) mice. Further, embryos flushed from Aire KO dams at GD3.5 were developmentally delayed in comparison to WT controls and had reduced trophoblastic outgrowth in vitro. We conclude that AIRE does not play a direct role in uterine decidualization. Rather, reduced fertility of Aire-deficient females is likely due to multiple factors, including oophoritis, delayed preimplantation development, and compromised implantation. These effects may be explained by autoimmune targeting of the ovary, embryo, or both. Alternatively, altered embryonic development could be due to a direct role for AIRE in early embryogenesis.

Micro-RNAs involved in cellular proliferation have altered expression profiles in granulosa of young women with diminished ovarian reserve

PURPOSE

The study aims to determine differences in micro-RNA (miRNA) expression in granulosa (GC) and cumulus cells (CC) between young women with diminished ovarian reserve (DOR) or normal ovarian reserve (NOR). Secondary objective was to identify downstream signaling pathways that could ultimately indicate causes of lower developmental competence of oocytes from young women with DOR.

METHODS

The method of the study is prospective cohort study.

RESULTS

Of the miRNA, 125 are differentially expressed in GC between DOR and NOR. Only nine miRNA were different in CC; therefore, we focused analysis on GC. In DOR GC, miR-100-5p, miR-16-5p, miR-30a-3p, and miR-193a-3p were significantly downregulated, while miR-155-5p, miR-192-5p, miR-128-3p, miR-486-5p, miR130a-3p, miR-92a-3p, miR-17-3p, miR-221-3p, and miR-175p were increased. This pattern predicted higher cell proliferation in the DOR GC. The primary pathways include MAPK, Wnt, and TGFbeta.

CONCLUSIONS

The miRNA pattern identified critical functions in cell proliferation and survival associated with DOR. GC in women with DOR seems to respond differently to the LH surge.

Stage-specific follicular extracellular vesicle uptake and regulation of bovine granulosa cell proliferation

Follicular fluid within ovarian antral follicles contains numerous factors, which influence the development of a healthy oocyte including nucleic acids, steroids, proteins, and extracellular vesicles (EVs). Current evidence indicates that follicular EVs promote changes in cellular gene expression and support cumulus-oocyte complex expansion in vitro. In this study, we found EVs from different sized follicles differentially stimulate granulosa cell proliferation and this could be explained by both the differential contents associated, on or within the vesicles and by the preferential uptake of EVs dependent on follicle size from which they were isolated. Antibody array and inhibitor studies indicated that the Src, PI3K/Akt, and MAPK signaling pathways mediate the stimulatory effects of EVs on granulosa cell proliferation. This study demonstrates for the first time that EVs isolated from follicular fluid are capable of stimulating granulosa cell proliferation and that this stimulatory response is associated with the size of antral follicle from which the EVs originated. The study further also provides the first evidence that vesicles released by small antral follicles are preferentially taken up when compared to those isolated from large follicles, suggesting that vesicular surface proteins change during follicular maturation.

Circulating microRNA as candidates for early embryonic viability in cattle

Blood-borne extracellular vesicles (i.e., exosomes and microvesicles) carrying microRNAs (miRNAs) could make excellent biomarkers of disease and different physiologic states, including pregnancy status. We tested the hypothesis that circulating extracellular vesicle-derived miRNAs might differentiate the pregnancy status of cows that had maintained pregnancy to Day 30 from non-pregnant cows or from those that exhibited embryonic mortality between Days 17 and 30 of gestation. Cows were randomly assigned for artificial insemination with fertile semen (n = 36) or dead semen (n = 8; control group) on Day 0 (day of estrus). Blood was collected from all animals on Day 0 and on Days 17 and 24 after artificial insemination. Cows receiving live sperm were retrospectively classified as pregnant on Day 30 (n = 17) or exhibiting embryonic mortality between Days 17 and 30 (n = 19). Extracellular vesicles from Day 17 and 24 samples were isolated from serum using ultra-centrifugation, and their presence was confirmed by nanoparticle tracking and Western blot analyses (for CD81) prior to RNA extraction. MicroRNA sequencing was performed on pregnant, embryonic-mortality, and control cows (n = 4 per day), for a total of 24 independent reactions. In total, 214 miRNAs were identified in serum, 40 of which were novel. Based on differential abundance parameters, we identified 32 differentially abundant loci, representing 27 differentially abundant mature miRNA. At Days 17 and 24, specific miRNAs (e.g., miR-25, -16b, and -3596) were identified that differentiated the pregnancy status. In summary, we identified several circulating extracellular vesicles derived miRNAs that differ in abundance between embryonic mortality and pregnant cows.

MicroRNA mediated regulation of immunity against gram-negative bacteria

Evidence over the last couple decades has comprehensively established that short, highly conserved, non-coding RNA species called microRNA (miRNA) exhibit the ability to regulate expression and function of host genes at the messenger RNA (mRNA) level. MicroRNAs play key regulatory roles in immune cell development, differentiation, and protective function. Intrinsic host immune response to invading pathogens rely on intricate orchestrated events in the development of innate and adaptive arms of immunity. We discuss the involvement of miRNAs in regulating these processes against gram negative pathogens in this review.

Abstract B05: The RNA-binding protein HuR enhances exosome secretion in colorectal cancer

Enhanced secretion of exosomes by cancer cells is recognized as a means of transferring oncogenic information within the tumor microenvironment. Through their ability to carry specific RNA and protein cargo, tumor-derived exosomes are now being recognized for their ability to impact the tumor microenvironment and as promising cancer biomarkers. However, our knowledge of the cellular factors that promote increased exosome production from tumor cells and how they impact the loading of specific tumor-promoting RNA cargo is limited. Our prior work has established that colorectal cancer (CRC) cells and tumors overexpress the key RNA-binding protein HuR (ELAVL1) early in GI tumor development. When overexpressed and present in the cytoplasm, HuR can promote mRNA stabilization of tumor-promoting genes through binding of 3'UTR AU-rich elements (ARE). These same mRNAs are within tumor-derived exosomes, suggesting a role for HuR. To test this, Tet-regulated HuR-inducible HeLa cells were used to demonstrate that cytoplasmic HuR overexpression promoted a 4-fold increase in exosome production. Furthermore, HuR was detected in exosomes produced only from HuR-overexpressing cells. The presence of HuR in exosomes directly impacted mRNA cargo, as selective uptake of ARE-containing mRNAs were observed in exosomes derived from HuR overexpressing cells. To assess if these effects were seen in CRC cells that endogenously overexpress HuR, exosome levels from CRC cells were compared to normal human intestinal epithelial and myofibroblast cells. CRC cells secrete ~3-fold greater exosome levels than normal cells and enhanced exosome production was dependent upon HuR. siRNA knockdown and CRISPER/Cas9 knockout of HuR in CRC cells showed a &gt;2-fold decrease in secreted exosomes, similar to the levels observed in normal cells. Furthermore, HuR knockout CRC cells showed a ~3-fold reduction in xenograft tumor growth compared to parental CRC cells. These findings were reflected in vivo where GI-tumor bearing APCMin/+ mice produced ~3-fold more serum exosomes, with HuR as exosomal cargo in APCMin/+ mice, whereas limited expression of exosomal HuR was detected in wild-type mice. This work has identified a novel connection between HuR-mediated post-transcriptional regulation and tumor-derived exosome production, along with providing the first preclinical evidence indicating the presence of exosomal HuR as a serum-based CRC biomarker.

Citation Format: Ranjan Preet, Wei-Ting Hung, Shufei Zhuang, Lane K. Christenson, Dan A. Dixon. The RNA-binding protein HuR enhances exosome secretion in colorectal cancer. [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer: From Initiation to Outcomes; 2016 Sep 17-20; Tampa, FL. Philadelphia (PA): AACR; Cancer Res 2017;77(3 Suppl):Abstract nr B05.

Stimuli-sensitive thiolated hyaluronic acid based nanofibers: synthesis, preclinical safety and in vitro anti-HIV activity

AIM

To develop a seminal enzyme bioresponsive, mucoadhesive nanofibers (NFs) as safe and effective nanocarriers for the prevention of HIV vaginal transmission.

METHODS

A novel thiolated hyaluronic acid (HA-SH) polymer was synthesized to fabricate tenofovir (TFV)-loaded electrospun NFs (HA-SH-NFs) and characterized in vitro/in vivo.

RESULTS

A triggered drug release (87% w/w) from the engineered HA-SH-NFs (mean diameter ∼75 nm) occured within 1 h under the influence of seminal hyaluronidase enzyme. HA-SH-NFs were noncytotoxic, induced no damage on the C57BL/6 mice genital-tract and other organs. No significant CD45 cell-infiltration and changes in cytokines level in cervicovaginal tissues were observed. HA-SH-NFs significantly enhanced both TFV retention and bioavailability in vaginal tissue compared with the 1% TFV-gel. The anti-HIV activity of TFV (on pseudotyped virus followed by luciferase assay) was not adversely affected by the electrospinning process.

CONCLUSION

HA-SH-NFs developed in this study could potentially serve as a safe nanotemplate for topical intravaginal delivery of HIV/AIDS microbicides.

Antigen specific immune response in Chlamydia muridarum genital infection is dependent on murine microRNAs-155 and -182

Anti-chlamydial immunity involves efficient presentation of antigens (Ag) to effector cells resulting in Ag-specific immune responses. There is limited information on inherent underlying mechanisms regulating these events. Previous studies from our laboratory have established that select microRNAs (miRs) function as molecular regulators of immunity in Chlamydia muridarum (Cm) genital infection. In this report, we investigated immune cell type-specific miRs, i.e. miR-155 and -182, and the role in Ag-specific immunity. We observed significant up-regulation of miR-155 in C57BL/6 bone marrow derived dendritic cells (BMDC), and miR-182 in splenic Ag-specific CD4+ T-cells. Using mimics and inhibitors, we determined that miR-155 contributed to BMDC activation following Cm infection. Co-cultures of miR-155 over-expressed in BMDC and miR-182 over-expressed in Ag-specific CD4+ T-cells, or miR-155-/- BMDC with miR-182 inhibitor treated Ag-specific CD4+ T-cells, resulted in IFN-γ production comparable to Ag-specific CD4+ T-cells isolated from Cm infected mice. Additionally, miR-182 was significantly up-regulated in intranasally vaccinated mice protected against Cm infection. In vivo depletion of miR-182 resulted in reduction in Ag-specific IFN-γ and genital pathology in Cm infected mice. To the best of our knowledge, this is the first study to report an interaction of miR-155 (in Cm infected DC) and miR-182 (in CD4+ T-cell) resulting in Ag specific immune responses against genital Cm.

Differentially expressed genes in preimplantation human embryos: potential candidate genes for blastocyst formation and implantation

Purpose

The aim of this study was to determine which genes and gene pathways are differentially expressed when comparing human blastocysts with cleavage-stage embryos.

Methods

We individually assessed gene expression in preimplantation human embryos at cleavage (n = 3) and blastocyst (n = 3) stages. Gene expression patterns were then validated in publically available datasets and then independently validated in vitro with additional human embryos using TaqMan gene expression assays. Immunolocalization studies were conducted to identify protein expression in intact blastocyst-stage embryos.

Results

Compared to cleavage-stage embryos, blastocyst-stage embryos differentially expressed 51 genes (p < 0.001), with overrepresentation in amoebiasis pathways and pathways in cancer. Of these 51 genes, 21 were found to be independently validated in a separate, publically available dataset, with a substantial agreement with our initial findings (κ = 0.8). In an independent set of cleavage- and blastocyst-stage embryos, we validated that six of eight tested genes were differentially expressed (p < 0.05) by RT-qPCR. Immunofluorescence studies documented the presence of two studied proteins in the trophectoderm of blastocyst-stage embryos.

Conclusions

Differentially expressed genes may be implicated in the invasion and proliferation of the early embryo. Our research highlights specific genes that may be further studied for their role in the implantation process and additionally raises questions about localized gene and/or protein expression in the trophectoderm, which could affect protocols for, and interpretation of, trophectoderm biopsies performed in in vitro fertilization cycles.

Electronic supplementary material

The online version of this article (doi:10.1007/s10815-016-0745-x) contains supplementary material, which is available to authorized users.

Characterization and Small RNA Content of Extracellular Vesicles in Follicular Fluid of Developing Bovine Antral Follicles

Exosomes and microvesicles (i.e., extracellular vesicles: EVs) have been identified within ovarian follicular fluid and recent evidence suggests that EVs are able to elicit profound effects on ovarian cell function. While existence of miRNA within EVs has been reported, whether EV size and concentration as well as their cargos (i.e., proteins and RNA) change during antral follicle growth remains unknown. Extracellular vesicles isolated from follicular fluid of small, medium and large bovine follicles were similar in size, while concentration of EVs decreased progressively as follicle size increased. Electron microscopy indicated a highly purified population of the lipid bilayer enclosed vesicles that were enriched in exosome biomarkers including CD81 and Alix. Small RNA sequencing identified a large number of known and novel miRNAs that changed in the EVs of different size follicles. Ingenuity Pathway Analysis (IPA) indicated that miRNA abundant in small follicle EV preparations were associated with cell proliferation pathways, while those miRNA abundant in large follicle preparations were related to inflammatory response pathways. These studies are the first to demonstrate that EVs change in their levels and makeup during antral follicle development and point to the potential for a unique vesicle-mediated cell-to-cell communication network within the ovarian follicle.

Composite Nanoformulation Therapeutics for Long-Term Ocular Delivery of Macromolecules

The purpose of this investigation is to design and synthesize novel pentablock (PB) copolymer (PB-1: PCL-PLA-PEG-PLA-PCL) based nanoformulations suspended in a thermosensitive gelling copolymer (PB-2: mPEG-PCL-PLA-PCL-PEGm) termed as composite nanoformulation. The composite nanoformulation was prepared to provide a sustained delivery of macromolecules over a longer duration with negligible burst release effect. The delivery system was designed to be utilized for the treatment of posterior segment ocular diseases such as age-related (wet) macular degeneration, diabetic retinopathy, and diabetic macular edema. The novel PB copolymers were characterized for their functional groups by Fourier transform infrared spectroscopy, molecular weight and purity by (1)H NMR spectroscopy, and gel permeation chromatography. X-ray diffraction analysis was used to determine the crystallinity of copolymers. The size distribution of PB-1 nanoparticles (NPs) prepared using emulsification-solvent evaporation method was found to be ∼150 nm analyzed by nanoparticle tracking analysis. The % encapsulation efficiency and % drug loading were found to be 66.64% w/w ± 1.75 and 18.17% w/w ± 0.39, respectively, (n = 3). Different weight percentages (15 and 20 wt %) of the PB-2 copolymer have been utilized for in vitro release studies of IgG-Fab from composite nanoformulation. A negligible burst release with continuous near zero-order release has been observed from the composite nanoformulation analyzed up to 80 days. In vitro cell viability and biocompatibility studies performed on ocular (human corneal epithelial and retinal pigment epithelium) and mouse macrophage (RAW 264.7) cell lines showed that the synthesized PB copolymer based composite nanoformulations were safe for clinical applications. On the basis of the results observed, it is concluded that PB copolymer based composite nanoformulations can serve as a platform for ocular delivery of therapeutic proteins. In addition, the composite nanoformulation may provide minimal side effects associated with frequent intravitreal injections.

Non-coding RNA in Ovarian Development and Disease

The ovary's primary function is to produce the mature female gamete, the oocyte that, following fertilization, can develop into an embryo, implant within the uterus and ultimately allow the mother's genetic material to be passed along to subsequent generations. In addition to supporting the generation of the oocyte, the ovary and specific ephemeral tissues within it, follicles and corpora lutea, produce steroids that regulate all aspects of the reproductive system, including the hypothalamic/pituitary axis, the reproductive tract (uterus, oviduct, cervix), secondary sex characteristics all of which are also essential for pregnancy and subsequent nurturing of the offspring. To accomplish these critical roles, ovarian development and function are tightly regulated by a number of exogenous (hypothalamic/pituitary) and endogenous (intraovarian) hormones. Within ovarian cells, intricate signalling cascades and transcriptional and post-transcriptional gene regulatory networks respond to these hormonal influences to provide the exquisite control over all of the temporal and spatial events that must be synchronized to allow this organ to successfully complete its function. This book chapter will focus specifically on the role of non-coding RNAs, their identification and described functional roles within the ovary with respect to normal function and their possible involvement in diseases, which involve the ovary.

Extracellular Vesicles from Bovine Follicular Fluid Support Cumulus Expansion

Expansion of the cumulus complex surrounding the oocyte is critical for ovulation of a fertilizable egg. The ovulation-inducing surge of luteinizing hormone leads to an increased expression of genes such as prostaglandin-endoperoxide synthase 2 (Ptgs2), pentraxin-related protein 3 (Ptx3), and tumor necrosis factor alpha-induced protein 6 (Tnfaip6) that support cumulus expansion. Factors released by mural granulosa and cumulus granulosa cells into the follicular fluid induce paracrine signaling within the follicular compartment. The follicular fluid that separates these distinct granulosa cell types is an enriched fluid containing numerous proteins, nucleic acids, and other macromolecules. Extracellular vesicles (EVs) are also present; however, no physiologically relevant functions of follicular EVs have yet been demonstrated. In our study, the effect of follicular EVs on cumulus-oocyte complex (COC) expansion and relevant gene expression was assayed. Follicular EVs were isolated using ultracentrifugation from follicular fluid of small (3-5 mm) and large (>9 mm) antral bovine follicles, then characterized by nanoparticle tracking analysis, electron microscopy, and Western blot analysis. To test for bioactivity, mouse and bovine COCs were cultured with follicular EVs. Cumulus expansion and Ptgs2, Ptx3, and Tnfaip6 gene expression were measured following COC maturation culture. The results demonstrated that follicular EVs can support both measurable cumulus expansion and increased gene expression.

Murine MicroRNA-214 regulates intracellular adhesion molecule (ICAM1) gene expression in genital Chlamydia muridarum infection

The hallmark of chlamydial infection is the development of upper genital pathology in the form of hydrosalpinx and oviduct and/or tubal dilatation. Although molecular events leading to genital tissue presentation and cellular architectural remodelling are unclear, early-stage host immune responses are believed to contribute to these long-term sequelae. Recently, we reported the contribution of selected infection-associated microRNAs (miRs) in the generation of host immunity at early-stage infection (day 6 after intravaginal Chlamydia muridarum challenge in C57BL/6 mice). In this report, we describe the contribution of an infection-associated microRNA, i.e. miR-214, to host immunity. Chlamydia muridarum infection in the C57BL/6 mouse genital tract significantly down-regulated miR-214 while up-regulating intracellular adhesion molecule 1 (ICAM1) gene expression. These in vivo observations were confirmed by establishing direct regulation of ICAM-1 by miR-214 in ex vivo genital cell cultures in the presence of miR-214 mimic and inhibitor. Because, ICAM-1 contributes to recruitment of neutrophils following infection, we also demonstrated that alteration of ICAM1 by miR-214 in interleukin-17A-deficient (IL-17A(-/-) ) mice correlated with reduction of neutrophils infiltrating genital tissue at day 6 after challenge. Additionally, these early-stage events resulted in significantly decreased genital pathology in IL-17A(-/-) mice compared with C57BL/6 mice. This report provides evidence for early-stage regulation of ICAM1 by microRNAs, resulting in reduction of genital pathology associated with chlamydial infection.

MicroRNA in Ovarian Biology and Disease

MicroRNAs (miRNAs) are posttranscriptional gene regulatory molecules that show regulated expression within ovarian tissue. Most research investigating miRNAs in the ovary has relied exclusively on in vitro analyses. In this review, we highlight those few studies in which investigators have illustrated an in vivo effect of miRNAs on ovarian function. We also provide a synopsis of how these small noncoding RNAs can impact ovarian disease. miRNAs have great potential as novel diagnostic biomarkers for the detection of ovarian disease and in the assisted reproductive technologies (ART) for selection of healthy viable oocytes and embryos.

Ovarian autoimmune disease: clinical concepts and animal models

The ovary is not an immunologically privileged organ, but a breakdown in tolerogenic mechanisms for ovary-specific antigens has disastrous consequences on fertility in women, and this is replicated in murine models of autoimmune disease. Isolated ovarian autoimmune disease is rare in women, likely due to the severity of the disease and the inability to transmit genetic information conferring the ovarian disease across generations. Nonetheless, autoimmune oophoritis is often observed in association with other autoimmune diseases, particularly autoimmune adrenal disease, and takes a toll on both society and individual health. Studies in mice have revealed at least two mechanisms that protect the ovary from autoimmune attack. These mechanisms include control of autoreactive T cells by thymus-derived regulatory T cells, as well as a role for the autoimmune regulator (AIRE), a transcriptional regulator that induces expression of tissue-restricted antigens in medullary thymic epithelial cells during development of T cells. Although the latter mechanism is incompletely defined, it is well established that failure of either results in autoimmune-mediated targeting and depletion of ovarian follicles. In this review, we will address the clinical features and consequences of autoimmune-mediated ovarian infertility in women, as well as the possible mechanisms of disease as revealed by animal models.

A detailed analysis of next generation sequencing reads of microRNA expression in Barrett's esophagus: absolute versus relative quantification

BACKGROUND

Next generation sequencing (NGS) is a state of the art technology for microRNA (miRNA) analysis. The quantitative interpretation of the primary output of NGS i.e. the read counts for a miRNA sequence that can vary by several orders of magnitude (1 to 107) remains incompletely understood.

FINDINGS

NGS (SOLiD 3 technology) was performed on biopsies from 6 Barrett's esophagus (BE) and 5 Gastroesophageal Reflux Disease (GERD) patients. Read sequences were aligned to miRBase 18.0. Differential expression analysis was adjusted for false discovery rate of 5%. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed for 36 miRNA in a validation cohort of 47 patients (27 BE and 20 GERD). Correlation coefficients, accuracy, precision and recall of NGS compared to qRT-PCR were calculated. Increase in NGS reads was associated with progressively lower Cq values, p < 0.05. Although absolute quantification between NGS reads and Cq values correlated modestly: -0.38, p = 0.01 for BE and -0.32, p = 0.05 for GERD, relative quantification (fold changes) of miRNA expression between BE &GERD by NGS correlated highly with qRT-PCR 0.86, p = 2.45E-11. Fold change correlations were unaffected when different thresholds of NGS read counts were compared (>1000 vs. <1000, >500 vs. <500 and >100 vs. <100). The accuracy, precision and recall of NGS to label a miRNA as differentially expressed were 0.71, 0.88 and 0.74 respectively.

CONCLUSION

Absolute NGS reads correlated modestly with qRT-PCR but fold changes correlated highly. NGS is robust at relative but not absolute quantification of miRNA levels and accurate for high-throughput identification of differentially expressed miRNA.

Extracellular vesicles in luminal fluid of the ovine uterus

Microvesicles and exosomes are nanoparticles released from cells and can contain small RNAs, mRNA and proteins that affect cells at distant sites. In sheep, endogenous beta retroviruses (enJSRVs) are expressed in the endometrial epithelia of the uterus and can be transferred to the conceptus trophectoderm. One potential mechanism of enJSRVs transfer from the uterus to the conceptus is via exosomes/microvesicles. Therefore, studies were conducted to evaluate exosomes in the uterine luminal fluid (ULF) of sheep. Exosomes/microvesicles (hereafter referred to as extracellular vesicles) were isolated from the ULF of day 14 cyclic and pregnant ewes using ExoQuick-TC. Transmission electron microscopy and nanoparticle tracking analysis found the isolates contained vesicles that ranged from 50 to 200 nm in diameter. The isolated extracellular vesicles were positive for two common markers of exosomes (CD63 and HSP70) by Western blot analysis. Proteins in the extracellular vesicles were determined by mass spectrometry and Western blot analysis. Extracellular vesicle RNA was analyzed for small RNAs by sequencing and enJSRVs RNA by RT-PCR. The ULF extracellular vesicles contained a large number of small RNAs and miRNAs including 81 conserved mature miRNAs. Cyclic and pregnant ULF extracellular vesicles contained enJSRVs env and gag RNAs that could be delivered to heterologous cells in vitro. These studies support the hypothesis that ULF extracellular vesicles can deliver enJSRVs RNA to the conceptus, which is important as enJSRVs regulate conceptus trophectoderm development. Importantly, these studies support the idea that extracellular vesicles containing select miRNAs, RNAs and proteins are present in the ULF and likely have a biological role in conceptus-endometrial interactions important for the establishment and maintenance of pregnancy.

Research resource: preovulatory LH surge effects on follicular theca and granulosa transcriptomes

The molecular mechanisms that regulate the pivotal transformation processes observed in the follicular wall following the preovulatory LH surge, are still not established, particularly for cells of the thecal layer. To elucidate thecal cell (TC) and granulosa cell (GC) type-specific biologic functions and signaling pathways, large dominant bovine follicles were collected before and 21 hours after an exogenous GnRH-induced LH surge. Antral GCs (aGCs; aspirated by follicular puncture) and membrane-associated GCs (mGCs; scraped from the follicular wall) were compared with TC expression profiles determined by mRNA microarrays. Of the approximately 11 000 total genes expressed in the periovulatory follicle, only 2% of thecal vs 25% of the granulosa genes changed in response to the LH surge. The majority of the 203 LH-regulated thecal genes were also LH regulated in GCs, leaving a total of 57 genes as LH-regulated TC-specific genes. Of the 57 thecal-specific LH-regulated genes, 74% were down-regulated including CYP17A1 and NR5A1, whereas most other genes are being identified for the first time within theca. Many of the newly identified up-regulated thecal genes (eg, PTX3, RND3, PPP4R4) were also up-regulated in granulosa. Minimal expression differences were observed between aGCs and mGCs; however, transcripts encoding extracellular proteins (NID2) and matrix modulators (ADAMTS1, SASH1) dominated these differences. We also identified large numbers of unknown LH-regulated GC genes and discuss their putative roles in ovarian function. This Research Resource provides an easy-to-access global evaluation of LH regulation in TCs and GCs that implicates numerous molecular pathways heretofore unknown within the follicle.

Developmental programming: gestational bisphenol-A treatment alters trajectory of fetal ovarian gene expression

Bisphenol-A (BPA), a ubiquitous environmental endocrine disrupting chemical, is a component of polycarbonate plastic and epoxy resins. Because of its estrogenic properties, there is increasing concern relative to risks from exposures during critical periods of early organ differentiation. Prenatal BPA treatment in sheep results in low birth weight, hypergonadotropism, and ovarian cycle disruptions. This study tested the hypothesis that gestational exposure to bisphenol A, at an environmentally relevant dose, induces early perturbations in the ovarian transcriptome (mRNA and microRNA). Pregnant Suffolk ewes were treated with bisphenol A (0.5 mg/kg, sc, daily, produced ∼2.6 ng/mL of unconjugated BPA in umbilical arterial samples of BPA treated fetuses approaching median levels of BPA measured in maternal circulation) from days 30 to 90 of gestation. Expression of steroidogenic enzymes, steroid/gonadotropin receptors, key ovarian regulators, and microRNA biogenesis components were measured by RT-PCR using RNA derived from fetal ovaries collected on gestational days 65 and 90. An age-dependent effect was evident in most steroidogenic enzymes, steroid receptors, and key ovarian regulators. Prenatal BPA increased Cyp19 and 5α-reductase expression in day 65, but not day 90, ovaries. Fetal ovarian microRNA expression was altered by prenatal BPA with 45 down-regulated (>1.5-fold) at day 65 and 11 down-regulated at day 90 of gestation. These included microRNAs targeting Sry-related high-mobility-group box (SOX) family genes, kit ligand, and insulin-related genes. The results of this study demonstrate that exposure to BPA at an environmentally relevant dose alters fetal ovarian steroidogenic gene and microRNA expression of relevance to gonadal differentiation, folliculogenesis, and insulin homeostasis.

A novel role of microRNA146b in promoting mammary alveolar progenitor cell maintenance

In this report, we have shown that miR146b promotes the maintenance of pregnancy-derived mammary luminal alveolar progenitors. MiR146b expression was significantly higher in the mammary glands of pregnant and lactating mice than in virgin mice. Furthermore, miR146b levels were significantly higher in mouse mammary glands exposed to the sex hormones, estrogen and progesterone, compared with those of untreated control animals. Pregnancy-derived primary mouse mammary epithelial cells in which miR146b was knocked down showed a significant reduction in the number of hollow acinar organoid structures formed on three-dimensional Matrigel and in β-casein expression. This demonstrates that miR146b promotes the maintenance of pregnancy-derived mammary luminal alveolar progenitors. It has been shown that mouse mammary luminal progenitors give rise to hollow organoid structures, whereas solid organoid structures are derived from stem cells. Among several miR146b targets, miR146b knockdown resulted in preferential STAT3β overexpression. In the primary mouse mammary epithelial cells, overexpression of STAT3β isoform caused mammary epithelial cell death and a significant reduction in β-casein mRNA expression. Therefore, we conclude that during pregnancy miR146b is involved in luminal alveolar progenitor cell maintenance, at least partially, by regulating STAT3β.

Discovery and validation of Barrett's esophagus microRNA transcriptome by next generation sequencing

Objective

Barrett's esophagus (BE) is transition from squamous to columnar mucosa as a result of gastroesophageal reflux disease (GERD). The role of microRNA during this transition has not been systematically studied.

Design

For initial screening, total RNA from 5 GERD and 6 BE patients was size fractionated. RNA <70 nucleotides was subjected to SOLiD 3 library preparation and next generation sequencing (NGS). Bioinformatics analysis was performed using R package “DEseq”. A p value<0.05 adjusted for a false discovery rate of 5% was considered significant. NGS-identified miRNA were validated using qRT-PCR in an independent group of 40 GERD and 27 BE patients. MicroRNA expression of human BE tissues was also compared with three BE cell lines.

Results

NGS detected 19.6 million raw reads per sample. 53.1% of filtered reads mapped to miRBase version 18. NGS analysis followed by qRT-PCR validation found 10 differentially expressed miRNA; several are novel (-708-5p, -944, -224-5p and -3065-5p). Up- or down- regulation predicted by NGS was matched by qRT-PCR in every case. Human BE tissues and BE cell lines showed a high degree of concordance (70–80%) in miRNA expression. Prediction analysis identified targets that mapped to developmental signaling pathways such as TGFβ and Notch and inflammatory pathways such as toll-like receptor signaling and TGFβ. Cluster analysis found similarly regulated (up or down) miRNA to share common targets suggesting coordination between miRNA.

Conclusion

Using highly sensitive next-generation sequencing, we have performed a comprehensive genome wide analysis of microRNA in BE and GERD patients. Differentially expressed miRNA between BE and GERD have been further validated. Expression of miRNA between BE human tissues and BE cell lines are highly correlated. These miRNA should be studied in biological models to further understand BE development.

Role of microRNA-21 and programmed cell death 4 in the pathogenesis of human uterine leiomyomas

OBJECTIVE

To determine whether programmed cell death 4 (PDCD-4) is altered in autologous leiomyoma and myometrial tissues and what microRNA-21's (miR-21) role is in PDCD-4 expression, apoptosis, and translation.

DESIGN

Laboratory research.

SETTING

Academic medical center.

PATIENT(S)

Myometrial and leiomyoma tissues from patients with symptomatic leiomyomata.

INTERVENTION(S)

Tissue analysis and miR-21 knockdown in cultured immortalized myometrial (UtM) and leiomyoma (UtLM) cells.

MAIN OUTCOME MEASURE(S)

MiR-21 and PDCD-4 mRNA and protein expression.

RESULT(S)

Leiomyoma tissues robustly expressed the full-length 51 kd isoform of PDCD-4, but normal myometrial tissue had negligible expression. Consistent with autologous tissues, UtLM cells expressed elevated miR-21 and a similar pattern of PDCD-4 compared with UtM cells. Knockdown of miR-21 increased PDCD-4 levels in UtM cells and UtLM cells, indicating that it can regulate PDCD-4 expression. Loss of miR-21 also increased cleavage of caspase-3 (apoptosis marker) and increased phosphorylation of elongation factor-2 (marker of reduced translation) in both cell lines.

CONCLUSION(S)

Elevated leiomyoma miR-21 levels are predicted to decrease PDCD-4 levels, thus leiomyomas differ from other tumors where loss of PDCD-4 is associated with tumor progression. Our studies indicate regulation of PDCD-4 expression is not a primary miR-21 function in leiomyomas, but instead miR-21 is able to impact cellular apoptosis and translation, through unknown targets, in a manner consistent with its involvement in the pathophysiology of uterine fibroids.

Developmental programming: gestational testosterone treatment alters fetal ovarian gene expression

Prenatal testosterone (T) treatment leads to polycystic ovarian morphology, enhanced follicular recruitment/depletion, and increased estradiol secretion. This study addresses whether expression of key ovarian genes and microRNA are altered by prenatal T excess and whether changes are mediated by androgenic or estrogenic actions of T. Pregnant Suffolk ewes were treated with T or T plus the androgen receptor antagonist, flutamide (T+F) from d 30 to 90 of gestation. Expression of steroidogenic enzymes, steroid/gonadotropin receptors, and key ovarian regulators were measured by RT-PCR using RNA obtained from fetal ovaries collected on d 65 [n = 4, 5, and 5 for T, T+F, and control groups, respectively] and d 90 (n = 5, 7, 4) of gestation. Additionally, fetal d 90 RNA were hybridized to multispecies microRNA microarrays. Prenatal T decreased (P < 0.05) Cyp11a1 expression (3.7-fold) in d 90 ovaries and increased Cyp19 (3.9-fold) and 5α-reductase (1.8-fold) expression in d 65 ovaries. Flutamide prevented the T-induced decrease in Cyp11a1 mRNA at d 90 but not the Cyp19 and 5α-reductase increase in d 65 ovaries. Cotreatment with T+F increased Cyp11a1 (3.0-fold) expression in d 65 ovaries, relative to control and T-treated ovaries. Prenatal T altered fetal ovarian microRNA expression, including miR-497 and miR-15b, members of the same family that have been implicated in insulin signaling. These studies demonstrate that maternal T treatment alters fetal ovarian steroidogenic gene and microRNA expression and implicate direct actions of estrogens in addition to androgens in the reprogramming of ovarian developmental trajectory leading up to adult reproductive pathologies.

Fer tyrosine kinase is required for germinal vesicle breakdown and meiosis-I in mouse oocytes

The control of microtubule and actin-mediated events that direct the physical arrangement and separation of chromosomes during meiosis is critical since failure to maintain chromosome organization can lead to germ cell aneuploidy. Our previous studies demonstrated a role for FYN tyrosine kinase in chromosome and spindle organization and in cortical polarity of the mature mammalian oocyte. In addition to Fyn, mammalian oocytes express the protein tyrosine kinase Fer at high levels relative to other tissues. The objective of the present study was to determine the function of this kinase in the oocyte. Feline encephalitis virus (FES)-related kinase (FER) protein was uniformly distributed in the ooplasm of small oocytes, but became concentrated in the germinal vesicle (GV) during oocyte growth. After germinal vesicle breakdown (GVBD), FER associated with the metaphase-I (MI) and metaphase-II (MII) spindles. Suppression of Fer expression by siRNA knockdown in GV stage oocytes did not prevent activation of cyclin dependent kinase 1 activity or chromosome condensation during in vitro maturation, but did arrest oocytes prior to GVBD or during MI. The resultant phenotype displayed condensed chromosomes trapped in the GV, or condensed chromosomes poorly arranged in a metaphase plate but with an underdeveloped spindle microtubule structure or chromosomes compacted into a tight sphere. The results demonstrate that FER kinase plays a critical role in oocyte meiotic spindle microtubule dynamics and may have an additional function in GVBD.

Mammalian oocytes are targets for prostaglandin E2 (PGE2) action

BACKGROUND

The ovulatory gonadotropin surge increases synthesis of prostaglandin E2 (PGE2) by the periovulatory follicle. PGE2 actions on granulosa cells are essential for successful ovulation. The aim of the present study is to determine if PGE2 also acts directly at the oocyte to regulate periovulatory events.

METHODS

Oocytes were obtained from monkeys and mice after ovarian follicular stimulation and assessed for PGE2 receptor mRNA and proteins. Oocytes were cultured with vehicle or PGE2 and assessed for cAMP generation, resumption of meiosis, and in vitro fertilization.

RESULTS

Germinal vesicle intact (GV) oocytes from both monkeys and mice expressed mRNA for the PGE2 receptors EP2, EP3, and EP4. EP2 and EP4 proteins were detected by confocal microscopy in oocytes of both species. Monkey and mouse oocytes responded to PGE2 as well as agonists selective for EP2 and EP4 receptors with elevated cAMP, consistent with previous identification of EP2 and EP4 as Gαs/adenylyl cyclase coupled receptors. Incubation of mouse GV stage oocytes with PGE2 delayed oocyte nuclear maturation in vitro, but PGE2 treatment did not alter the percentage of mouse oocytes that fertilized successfully. PGE2 treatment also decreased the percentage of monkey oocytes that resumed meiosis in vitro. In contrast with mouse oocytes, the percentage of monkey oocytes which fertilized in vitro was lower after treatment with PGE2. Monkey oocytes with intact cumulus showed delayed nuclear maturation, but fertilization rate was not affected by PGE2 treatment.

CONCLUSIONS

Monkey and mouse oocytes express functional PGE2 receptors. PGE2 acts directly at mammalian oocytes to delay nuclear maturation. Surrounding cumulus cells modulate the effect of PGE2 to alter subsequent fertilization.