Project description:Preterm birth (PTB) is defined as childbirth occurring at less than 37 completed weeks or 259 days of gestation. Premature babies have higher rates of cerebral palsy, sensory deficits, learning disabilities and respiratory illnesses that extend into adulthood. This lifelong morbidity results in high economic and social costs to families and communities. PTB is a syndrome initiated by multiple mechanisms, including infection or inflammation, uteroplacental ischaemia or haemorrhage, uterine overdistension, stress, and other immunologically mediated processes. Identifying and monitoring molecular signals in easily accessible body fluids that can diagnose or predict the risk of preterm labor in pregnant women will reduce or prevent PTBs. A number of studies reported the identification of putative biomarkers for PTB including protein, miRNA and hormone from different body fluids such as serum/plasma, cervical vaginal fluid, saliva and amniotic fluids. These putative biomarkers identified can largely be grouped into three main functional categories: inflammatory related molecules, placenta or fetal derived molecules and stress related molecules. In the past few years next generation sequencing (NGS) has become the major platform for miRNA analysis especially with body fluids. However, studies have shown significant sequence bias among different small RNA library preparation protocols. We have modified the small RNA library construction protocol which greatly reduces the sequence bias and increase miRNA coverage in sample. We also adapted a newly developed size exclusion chromatography (SEC) based EV purification protocol which can provide cleaner EVs compared to other methods. We are using these improved approaches to gain more reliable profile of circulating RNA in body fluid as well as its associated EVs. With these new approaches, we explore the possibility of using specific circulating miRNAs, specifically those encapsulated in EVs, as a noninvasive biomarker for PTB by comparing the miRNA profiles in maternal plasma, EV and EV-depleted plasma between individuals who had a spontaneous preterm birth and uncomplicated pregnancies.

Project description:Ovarian follicular fluid (FF) comprises a dynamic milieu whose composition alters under seasonal variation, influencing follicle development and oocyte developmental competence. Various cell subtypes (e.g. granulosa, theca, and cumulus) produce cell-secreted nanoparticles, coined extracellular vesicles (EVs), which contain bioactive regulatory molecules such as microRNAs (miRNAs) known to mediate intrafollicular communication through various forms of signaling and information transfer. Markedly, the hallmark feature of EVs transferring cellular knowledge propagates their appealing nature as direct indicators of cellular status, albeit homeostasis, dysfunction, or disease. Photoperiod alterations influencing the regulatory content of FF-EVs as downstream modifiers remain largely unknown, particularly in seasonal breeding animals. Here, we aimed to unpack the impacts of seasonal variation on the miRNA expression profiles of FF-EVs in the mare. Equine pre-ovulatory follicles were monitored and aspirated using ultrasound-guided transvaginal techniques to obtain follicular fluids during non-breeding (spring anovulatory, SAN) and breeding seasons (spring ovulatory, SOV; summer, SUM; and fall ovulatory, FOV). 97 miRNAs were found to be differentially expressed between groups. Pairwise comparisons revealed specific clusters, including six miRNAs involved in the spring transition (miR-149-200b-206-221-328-615) and many others dysregulated during that of the summer (miR-143-192451- 302b-100, and let 7c), the peak time point for breeding. Bioinformatic analyses led to unveiling significant enrichments in various biological functions, such as transcription factor activity, transcription and transcription regulation, nucleic acid binding, sequence-specific DNA binding, p53 signaling, and post-translational modifications. Ultimately, the miRNA content of seasonally divergent FF-EVs poses as potentially relevant indicators of intrafollicular mechanisms directing seasonal transitions and their functional regulatory roles in the pre-ovulatory stage, governing subsequent ovulation.

Project description:Currently, micro RNAs (miRNAs) constitute a promising models for cell-to-cell communication since they are transferred between cells to execute essential roles in many processes. Their structure and size, in addition to various transport mechanisms, allow them to remain stable within various biological fluids, surviving in extremely adverse conditions, including low pH, boiling, and freezing. The presence of miRNAs in reproductive fluids, such as follicular, uterine and seminal fluid, indicate potential roles in the reproductive system. These extracellular miRNAs can be transported by lipoproteins (both HDL and LDL) or other proteins, including Argonaute2 (AGO2) and nucleophosmin1 (NPM1). Another transport system is mediated by extracellular vesicles (EVs), such as apoptotic bodies, microvesicles (MVs) and/or exosome-like vesicles. EVs protect miRNAs from degradation and contribute to their stability within biological fluids. Furthermore, EVs can transport a wide range of components packaged in a selective way. For instance, Squadrito et al. (2014), used macrophages and endothelial cells to demonstrate that the sorting of miRNAs into EVs for heterotrophic cell communication is altered by both, the presence of target transcripts and the self-presence of the respectively miRNA. In addition, the signature of miRNAs found in the exosomes significantly differed for those detected in the parent cells. To date, mechanisms controlling the specific loading of miRNAs into exosomes remain unclear. Indeed, several mechanisms may govern exosome sorting of specific subsets of miRNAs. MiRNA sorting appears to be influenced by different pathways and molecules in different cell types and tissues, and miRNAs contain well defined motifs (i.e., EXOmotifs), that direct the miRNA allocation into exosomes before delivery into recipient cells. A recent study showed that this RNA sequence can be recognized by the sumoylated form of the heterogeneous ribonucleoprotein A2B1 (hnRNPA2B1). Moreover, a terminal 30 nucleotide addition in miRNAs affects their selective sorting in B cells. Another hypothesis suggests that RNAs are selectively sorted depending on the differential affinity of RNA motifs towards the raft-like region of the cytoplasmic surface of microvesicular body (MVB) limiting membranes. Current data indicate that cells can communicate with each other through the transfer of miRNA-loaded exosomes. For example, monocyte-derived exosomes deliver miR-150 to endothelial cells and enhance endothelial cell migration by reducing c-myb expression. The miRNA content of exosomes plays a critical role in such cell-to-cell communication and determines the fate of recipient cells. Thus, exosomes derived from the bone marrow mesenchymal stromal cells of myeloma patients promote tumor growth depending on the content of miR-15a in exosomes. Our group has described a novel cell-to-cell communication mechanism involving the delivery of endometrial miRNAs from the maternal endometrium to the trophectoderm cells of preimplantation embryos. Specifically, in B6C3 derived mouse embryos, we found EV-associated and free miR-30d to cause overexpression of genes involved in embryonic adhesion processes, including Itb3, Itga7 and Cdh5. Furthermore, supplementing murine embryos with miR-30d significantly improved embryo adhesion, suggesting that external miRNAs may have a functional role as transcriptomic modifiers of preimplantation embryos. Based on profiling of miRNAs in endometrial fluid, maternally-derived miRNAs are present within EVs in the uterine microenvironment. The internalization of maternally-derived exosomes has been visualized, but the mechanism by which miR-30d becomes incorporated into exosomes remains unknown. The present study aimed to elucidate the underlying mechanism of hsa-miR-30d transfer from human endometrial epithelial cells (hEECs) to the interior of exosomes and eventually to early-stage blastocysts, using a mir-30d knockout murine mode.

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