SINE RNA of the imprinted miRNA clusters mediates constitutive type III interferon expression and antiviral protection in hemochorial placentas

Hemochorial placentas have evolved defense mechanisms to prevent the vertical transmission of viruses to the immunologically underdeveloped fetus. Unlike somatic cells that require pathogen-associated molecular patterns to stimulate interferon production, placental trophoblasts constitutively produce type III interferons (IFNL) through an unknown mechanism. We demonstrate that transcripts of short interspersed nuclear elements (SINEs) embedded in miRNA clusters within the placenta trigger a viral mimicry response that induces IFNL and confers antiviral protection. Alu SINEs within primate-specific chromosome 19 (C19MC) and B1 SINEs within rodent-specific microRNA cluster on chromosome 2 (C2MC) produce dsRNAs that activate RIG-I-like receptors (RLRs) and downstream IFNL production. Homozygous C2MC knockout mouse trophoblast stem (mTS) cells and placentas lose intrinsic IFN expression and antiviral protection, whereas B1 RNA overexpression restores C2MCΔ/Δ mTS cell viral resistance. Our results uncover a convergently evolved mechanism whereby SINE RNAs drive antiviral resistance in hemochorial placentas, placing SINEs as integral players in innate immunity.

The hsa-miR-516a-5p and hsa-miR-516b-5p microRNAs reduce the migration and invasion on T98G glioblastoma cell line

microRNAs (miRNAs) are involved in numerous functions and processes in the brain and other organs through the regulation of gene and protein expression. miRNA dysregulation is associated with the development of several diseases, including the brain and Central Nervous System cancer (CNS). The hsa-miR-516a-5p and hsa-miR-516b-5p are involved in proliferation, migration, and invasion in different tumor models, but their antitumor effect has not been evaluated in cancer of CNS. Therefore, we aimed to assess the effect of the miRNAs hsa-miR-516a-5p and miRNA hsa-miR-516b-5p on the Glioblastoma cell line (T98G). We used synthetic miRNA mimics to induce the overexpression of both miRNAs in the cell line, which was corroborated by RT-qPCR. Next, we evaluated the effect on proliferation, migration, and invasion using the CyQuant direct kit, ThinCert ™ inserts and invasion BioCoat ™ Matrigel® Invasion Chambers. We found upregulation of these miRNAs induced significant changes on the migration and invasion processes of T98G cells, but not affected the proliferation rate. These results suggest that both microRNAs could be playing an important role in the control of tumor progression towards metastasis. The bioinformatics analysis showed that target genes for these miRNAs are involved in different biological processes such as in cell adhesion molecule binding and cell junction disassembly, which are important for cancer progression. Further studies and experimental validation are needed to identify the genes regulated by microRNAs.

The Autocrine Role of Placental Extracellular Vesicles from Missed Miscarriage in Causing Senescence: Possible Pathogenesis of Missed Miscarriage

Placental dysfunction, including senescent changes, is associated with the pathogenesis of missed miscarriage, although the underlying mechanism is unclear. Increasing evidence indicates that placenta-specific miRNAs are packaged in extracellular vesicles (EVs) from placental syncytiotrophoblasts and are released into the maternal circulation. Aberrant cargos including miRNAs in placental EVs have been reported to be associated with the pathogenesis of complicated pregnancies. In this study, we compared the miRNA profiles in EVs derived from missed miscarriage and healthy placentae and investigated possible biological pathways which may be involved in senescence, one cause of missed miscarriage. The total concentration of RNA in placental EVs was not different between the two groups. However, there were 54 and 94 differentially expressed miRNAs in placental large and small EVs from missed miscarriage compared to EVs from healthy controls. The aberrantly expressed miRNAs seen in placental EVs were also observed in missed miscarriage placentae. Gene enrichment analysis showed that some of those differentially expressed miRNAs are involved in cellular senescence, endocytosis, cell cycle and endocrine resistance. Furthermore, transfection of trophoblasts by a single senescence-associated miRNA that was differentially expressed in placental EVs derived from missed miscarriage did not cause trophoblast dysfunction. In contrast, EVs derived from missed miscarriage placenta induced senescent changes in the healthy placenta. Our data suggested that a complex of placental EVs, rather than a few differentially expressed miRNAs in placental EVs derived from missed miscarriage placentae could contribute in an autocrine manner to placental senescence, one of the causes of missed miscarriage.

The Role of Cluster C19MC in Pre-Eclampsia Development

Pre-eclampsia is a placenta-related complication occurring in 2-10% of all pregnancies. miRNAs are a group of non-coding RNAs regulating gene expression. There is evidence that C19MC miRNAs are involved in the development of the placenta. Deregulation of chromosome 19 microRNA cluster (C19MC) miRNAs expression leads to impaired cell differentiation, abnormal trophoblast invasion and pathological angiogenesis, which can lead to the development of pre-eclampsia. Information was obtained through a review of articles available in PubMed Medline. Articles on the role of the C19MC miRNA in the development of pre-eclampsia published in 2009-2022 were analyzed. This review article summarizes the current data on the role of the C19MC miRNA in the development of pre-eclampsia. They indicate a significant increase in the expression of most C19MC miRNAs in placental tissue and a high level of circulating fractions in serum and plasma, both in the first and/or third trimester in women with PE. Only for miR-525-5p, low levels of plasma expression were noted in the first trimester, and in the placenta in the third trimester. The search for molecular factors indicating the development of pre-eclampsia before the onset of clinical symptoms seems to be a promising diagnostic route. Identifying women at risk of developing pre-eclampsia at the pre-symptomatic stage would avoid serious complications in both mothers and fetuses. We believe that miRNAs belonging to cluster C19MC could be promising biomarkers of pre-eclampsia development.

Clinical Management of Embryonal Tumor with Multilayered Rosettes: The CCMC Experience

OBJECTIVE

Embryonal tumors with multilayered rosettes (ETMRs) are highly aggressive pediatric brain tumors with poor prognosis. No standard treatment strategy for them exists because of their rarity. This study aimed to share experiences on the clinical diagnosis and treatment of ETMRs at China Children's Medical Center (CCMC).

METHODS

Patients who received a diagnosis of an ETMR between January 2017 and June 2020 were included. Clinical characteristics, such as age of onset, tumor size, stage, tumor site, treatment strategy, and clinical outcome, were retrospectively analyzed.

RESULTS

There were four boys and one girl within 4 years who received a diagnosis during this 4-year timeframe, and were thus included. The average age of morbidity was 29 months (range 16-66 months). The common clinical presentation was headaches and nausea caused by intracranial hypertension. All four patients were chromosome 19 microRNA cluster (C19MC) amplification positive. Two patients achieved complete remission, and one patient attained partial remission after multimodal treatment. Of the two deaths, one died from the rapid progression of the disease and another from tumor-related complications.

CONCLUSION

ETMRs are extremely rare brain tumors with a high, early mortality in children. Surgery is the mainstream treatment for ETMRs. Some patients may also benefit from postoperative adjuvant chemotherapy and radiotherapy.

Prognostic impact of the multimodal treatment approach in patients with C19MC-altered embryonal tumor with multilayered rosettes

OBJECTIVE

Embryonal tumor with multilayered rosettes (ETMR) is one of the childhood central nervous system tumors with the poorest prognosis; thus, establishing an optimal treatment strategy is essential, However, because of the low incidence and molecular heterogeneity of the tumor, the optimal treatment has not yet been determined. In this study the authors evaluated the prognostic impact of a multimodal treatment approach in patients with ETMR.

METHODS

The authors evaluated 4 patients with ETMR at their institution who showed varied clinical features and also conducted clinical characterization and prognostic analysis of previously reported cases of the ETMR-presenting locus 19q13.42 with a chromosome 19 microRNA cluster (C19MC) amplification, which is known to be a diagnostic hallmark of the tumor.

RESULTS

Of the 4 patients with ETMR in the authors' institution, in 1 case the patient's tumor showed a neuroblastoma-like appearance without multilayered rosettes; however, the diagnosis was confirmed by the presence of amplified C19MC. From a clinical standpoint, 2 patients who underwent gross-total resection (GTR) of the tumor and chemotherapy followed by high-dose chemotherapy (HDC) had long-term complete remission with or without local irradiation. In the multivariate analysis of 43 cases with C19MC-altered ETMR reported in the literature, HDC and local irradiation were significantly correlated with better event-free survival (HR 0.17, p = 0.0087; HR 0.17, p = 0.010) and overall survival (OS) (HR 0.29, p = 0.023; HR 0.28, p = 0.019), respectively. GTR was also correlated with better OS (HR 0.40, p = 0.039).

CONCLUSIONS

This case series demonstrated pathological and clinical heterogeneity among ETMR cases and the diagnostic importance of the molecular genetic approach among embryonal tumors, particularly during infancy. Based on the results of the analysis of molecularly uniformed ETMR cases, multimodal treatment may play a significant role in the prognosis of these tumors.

A surgical case of pediatric spinal medulloepithelioma

Embryonal tumor with multilayered rosettes (ETMR), C19MC-altered was introduced to the World Health Organization classification of central nervous system tumors in 2016. It is characterized by amplification or fusion of the chromosome 19 microRNA cluster (C19MC) locus at 19q13.42. Medulloepithelioma also an ETMR but lacks C19MC alteration. We report a rare case of spinal medulloepithelioma in a 2-year-old boy and review the literature.

A 2-year-old girl with posterior fossa mass

We present a rare case of an ETMR with co‐occurrence of DICER1 and H3 K27M mutations.

Large-scale transcriptome-wide profiling of microRNAs in human placenta and maternal plasma at early to mid gestation

MicroRNAs (miRNAs) are increasingly seen as important regulators of placental development and opportunistic biomarker targets. Given the difficulty in obtaining samples from early gestation and subsequent paucity of the same, investigation of the role of miRNAs in early gestation human placenta has been limited. To address this, we generated miRNA profiles using 96 placentas from presumed normal pregnancies, across early gestation, in combination with matched profiles from maternal plasma. Placenta samples range from 6 to 23 weeks' gestation, a time period that includes placenta from the early, relatively low but physiological (6-10 weeks' gestation) oxygen environment, and later, physiologically normal oxygen environment (11-23 weeks' gestation).We identified 637 miRNAs with expression in 86 samples (after removing poor quality samples), showing a clear gestational age gradient from 6 to 23 weeks' gestation. We identified 374 differentially expressed (DE) miRNAs between placentas from 6-10 weeks' versus 11-23 weeks' gestation. We see a clear gestational age group bias in miRNA clusters C19MC, C14MC, miR-17 ~ 92 and paralogs, regions that also include many DE miRNAs. Proportional change in expression of placenta-specific miRNA clusters was reflected in maternal plasma.The presumed introduction of oxygenated maternal blood into the placenta (between ~10 and 12 weeks' gestation) changes the miRNA profile of the chorionic villus, particularly in placenta-specific miRNA clusters. Data presented here comprise a clinically important reference set for studying early placenta development and may underpin the generation of minimally invasive methods for monitoring placental health.

Central role of the placenta during viral infection: Immuno-competences and miRNA defensive responses

Pregnancy is a unique immunological condition in which an "immune-diplomatic" dialogue between trophoblasts and maternal immune cells is established to protect the fetus from rejection, to create a privileged environment in the uterus and to simultaneously be alert to any infectious challenge. The maternal-placental-fetal interface (MPFI) performs an essential role in this immunological defense. In this review, we will address the MPFI as an active immuno-mechanical barrier that protects against viral infections. We will describe the main viral infections affecting the placenta and trophoblasts and present their structure, mechanisms of immunocompetence and defensive responses to viral infections in pregnancy. In particular, we will analyze infection routes in the placenta and trophoblasts and the maternal-fetal outcomes in both. Finally, we will focus on the cellular targets of the antiviral microRNAs from the C19MC cluster, and their effects at both the intra- and extracellular level.

C19MC amplification and expression of Lin28A and Olig2 in the classification of embryonal tumors of the central nervous system: A 14-year retrospective study from a tertiary care center

INTRODUCTION

CNS embryonal tumors (CET) other than medulloblastomas (MB) and atypical teratoid/rhabdoid tumors (AT/RTs), previously designated as 'central nervous system primitive neuroectodermal tumors' ('CNS PNETs'), are a heterogenous subset of tumors with poorly defined diagnostic criteria. Other than the subset of embryonal tumor with multilayered rosettes (ETMR) defined by C19MC amplification, most CETs are diagnosed by exclusion of other molecularly defined entities and histological mimics including MB, AT/RTs, and high-grade gliomas, and termed as CET, not otherwise specified (NOS) in the 2016 WHO classification.

AIM

To reclassify 'CNS PNETs' as per WHO 2016, and estimate the true proportion of CET, NOS in a tertiary healthcare setting, and to evaluate the diagnostic utility of C19MC amplification, Lin28A and Olig2 expression in the subclassification of CETs.

METHODS

Previously diagnosed cases of 'CNS PNETs' (2002-2016) were first evaluated by immunohistochemistry (IHC) for MIC2, RelaA, L1CAM, IDH1R132H, H3K27M, H3G34R, H3G34V, INI1, and BRG1 proteins and by fluorescence in-situ hybridization (FISH) for EWSR1 translocation to exclude histological mimics. The selected CETs (case cohort) and 79 histological mimics (comparison cohort) comprising of MB, AT/RT, pineal parenchymal tumors, Ewing sarcoma, esthesioneuroblastoma, intraocular medulloepithelioma, and H3G34R mutant high-grade glioma were subject to IHC for Olig2 and Lin28A, and FISH for C19MC amplification.

RESULTS

Twenty-two cases of 'CNS PNETs' were retrieved, all of which were negative for the first panel of markers and showed retained INI-1/BRG1 expression. Three of them (3/22, 13.6%) showed C19MC amplification (ETMR, C19MC-altered) with ETMR histology, Lin28A positivity, and Olig2 negativity. Among the remaining 19 CETs, one showed medulloepithelioma histology (Medulloepithelioma, NOS) and remaining were non-descript small round cell tumors (CET, NOS), all negative for Lin28A. Olig2 was positive in only 3 CETs (13.6%), all being CET, NOS. All tumors in the comparison cohort were negative for C19MC amplification, Lin28A and Olig2 except for 27% of ATRTs that were Lin28A positive.

CONCLUSION

ETMR, C19MC-altered constitute less than 14% of CETs, with majority remaining uncharacterized as CET, NOS. Lin28A is 100% sensitive for the detection of C19MC amplification; however, its specificity is limited by its expression in ATRTs. Olig2 expression is seen only in a small subset of CET, NOS and is of limited diagnostic utility.

The expression of miRNA encoded by C19MC and miR-371-3 strongly varies among individual placentas but does not differ between spontaneous and induced abortions

miRNAs of the largest human miRNA gene cluster at all, i.e., C19MC, are almost exclusively expressed in the placenta. Nevertheless, only little is known about the interindividual variation of their expression and even about possible influence of gestational age, conflicting data is reported as well as for miRNAs of the much smaller miR-371-3 cluster. Our present study aims at the analyses of the expression of miRNAs from both clusters at different times of pregnancy, possible differences between placenta samples obtained from spontaneous or induced abortions in the first trimester, and the possible variation of miRNA expression at different sites within same placentas. miR-371a-3p, miR-372-3p, miR-373-3p, miR-517a-3p, and miR-520c-3p were quantified in 85 samples and miR-371a-3p was quantified in maternal serum samples taken immediately before delivery. While for miRNA-517a-3p and miR-520c-3p the expression increased with increasing gestational age, the present study revealed strong interindividual differences in the expression of miR-371-3 in full-term placental tissue as well as for miRNAs of the C19MC cluster, where the levels differed to a much lesser extent than for the former microRNAs. Also, strong interindividual differences were noted between the serum samples but differences related to the site of the placenta where the sample has been taken from were excluded. For neither of the data from placental tissue, the study revealed differences between the spontaneous and induced abortion group. Thus, the differences do not in general seem to be related to first trimester abortion. It remains to be elucidated whether or not they affect other prenatal processes.

Unc-13 homolog D mediates an antiviral effect of the chromosome 19 microRNA cluster miR-517a

The function of microRNAs (miRNAs) can be cell autonomous or communicated to other cell types and has been implicated in diverse biological processes. We previously demonstrated that miR-517a-3p (miR-517a), a highly expressed member of the chromosome 19 miRNA cluster (C19MC) that is transcribed almost exclusively in human trophoblasts, attenuates viral replication via induction of autophagy in non-trophoblastic recipient cells. However, the molecular mechanisms underlying these effects remain unknown. Here, we identified unc-13 homolog D (UNC13D) as a direct, autophagy-related gene target of miR-517a, leading to repression of UNC13D. In line with the antiviral activity of miR-517a, silencing UNC13D suppressed replication of vesicular stomatitis virus (VSV), whereas overexpression of UNC13D increased VSV levels, suggesting a role for UNC13D silencing in the antiviral activity of miR-517a. We also found that miR-517a activated NF-κB signaling in HEK-293XL cells expressing TLR8, but the effect was not specific to C19MC miRNA. Taken together, our results define mechanistic pathways that link C19MC miRNA with inhibition of viral replication.

Tissue-specific and transcription-dependent mechanisms regulate primary microRNA processing efficiency of the human chromosome 19 MicroRNA cluster

One of the longest human microRNA (miRNA) clusters is located on chromosome 19 (C19MC), containing 46 miRNA genes, which were considered to be expressed simultaneously and at similar levels from a common long noncoding transcript. Investigating the two tissue types where C19MC is exclusively expressed, we could show that there is a tissue-specific and chromosomal position-dependent decrease in mature miRNA levels towards the 3' end of the cluster in embryonic stem cells but not in placenta. Although C19MC transcription level is significantly lower in stem cells, this gradual decrease is not present at the primary miRNA levels, indicating that a difference in posttranscriptional processing could explain this observation. By depleting Drosha, the nuclease component of the Microprocessor complex, we could further enhance the positional decrease in stem cells, demonstrating that a tissue-specific, local availability of the Microprocessor complex could lie behind the phenomenon. Moreover, we could describe a tissue-specific promoter being exclusively active in placenta, and the epigenetic mark analysis suggested the presence of several putative enhancer sequences in this region. Performing specific chromatin immunoprecipitation followed by quantitative real-time PCR experiments we could show a strong association of Drosha with selected enhancer regions in placenta, but not in embryonic stem cells. These enhancers could provide explanation for a more efficient co-transcriptional recruitment of the Microprocessor, and therefore a more efficient processing of pri-miRNAs throughout the cluster in placenta. Our results point towards a new model where tissue-specific, posttranscriptional 'fine-tuning' can differentiate among miRNAs that are expressed simultaneously from a common precursor.

Embryonal tumors with multi-layered rosettes: a disease of dysregulated miRNAs

INTRODUCTION

ETMRs are highly lethal, pediatric embryonal brain tumors, previously classified as various histologic diagnoses including supratentorial primitive neuroectodermal tumors (sPNET) and CNS PNET. With recognition that these tumors harbor recurrent amplification of a novel oncogenic miRNA cluster on chr19, C19MC, ETMRs were designated as a distinct biological and molecular entity with a spectrum of histologic and clinical manifestations.

METHODS

We reviewed published literature describing clinical presentation, the genetic and epigenetic drivers of oncogenesis, and recent therapeutic strategies adopted to combat these aggressive tumors.

RESULTS

As a consequence of C19MC amplification, ETMRs upregulate several oncogenic and pluripotency proteins, including LIN28A, DNMT3B and MYCN, that confer a unique epigenetic signature reminiscent of nascent embryonic stem cells. In this review, we focus on the dysregulation of miRNAs in ETMR, the major pathogenic mechanism identified in this disease.

CONCLUSION

Despite the use of multi-modal therapeutic regimens, ETMR patients have dismal survival. Understanding the unique biology of these tumors has provided new insights towards novel therapeutic targets.

Circulating microRNAs as biomarkers to assist the management of the malignant germ-cell-tumour subtype choriocarcinoma

•

Current biomarkers have limited utility for management of germ-cell-tumours.

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Limitations include secretion restricted to specific subtypes and long half-life.

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Limitations can make interpretation and clinical decision-making challenging.

•

Circulating microRNAs show promise for management of these tumours.

•

We identify specific circulating microRNAs for the choriocarcinoma subtype.

Germ-cell-tumours (GCTs) are heterogeneous and management is complex. The current conventional biomarkers, alpha-fetoprotein and human-chorionic-gonadotropin (HCG), have limited utility for diagnosis/follow-up as secretion is restricted to specific malignant-GCT subtypes and long half-life can make interpretation and clinical decision-making challenging. We sought to identify circulating microRNAs that reflected choriocarcinoma disease activity more accurately than HCG in a metastatic primary mediastinal nonseminomatous-GCT (PMNSGCT) case with elevated diagnostic serum HCG (>250,000 U/L), consistent with pure choriocarcinoma. We undertook comprehensive microRNA profiling (n = 754 microRNAs) using two 384-well TaqMan Low-Density-Array cards in 16 serum samples; 10 from PMNSGCT diagnosis/follow-up and six controls. Key findings underwent confirmatory qRT-PCR. We identified a serum panel of choriocarcinoma-specific ‘chromosome-19-microRNA-cluster’ (C19MC) microRNAs that were highly elevated at diagnosis but fell rapidly on treatment and normalised before the second full chemotherapy course. We also re-confirmed serum elevation of the previously identified malignant-GCT marker miR-371a-3p at diagnosis. These circulating microRNA markers reflected choriocarcinoma disease activity more accurately than serum HCG and real-time knowledge would have assisted clinical decision-making. With further study, these microRNA markers will facilitate future management of such patients and are likely to result in improved outcomes.

Transgenic expression of human C19MC miRNAs impacts placental morphogenesis

INTRODUCTION

The chromosome 19 miRNA cluster (C19MC) encodes a large family of microRNAs (miRNAs) that are abundantly expressed in the placenta of higher primates and also in certain cancers. In the placenta, miRNAs from this cluster account for nearly 40% of all miRNAs present in trophoblasts. However, the function of these miRNAs in the placenta remains poorly understood. Recent observations reveal a role for these miRNAs in cell migration, and suggest that they are involved in the development and function of the human placenta. Here, we examine the placenta in transgenic mice expressing the human C19MC miRNAs.

METHODS

We produced transgenic mice using pronuclear microinjection of a bacterial artificial chromosome plasmid carrying the entire human C19MC locus and derived a homozygous line using crossbreeding. We performed morphological characterization and profiled gene expression changes in the placentas of the transgenic mice.

RESULTS

C19MC transgenic mice delivered on time with no gross malformations. The placentas of transgenic mice expressed C19MC miRNAs and were larger than wild type placentas. Histologically, we found that the transgenic placenta exhibited projections of spongiotrophoblasts that penetrated deep into the labyrinth. Gene expression analysis revealed alterations in the expression of several genes involved in cell migration, with evidence of enhanced cell proliferation.

DISCUSSION

Mice that were humanized for transgenically overexpressed C19MC miRNAs exhibit enlarged placentas with aberrant delineation of cell layers. The observed phenotype and the related gene expression changes suggest disrupted migration of placental cell subpopulations.

The Evolution of Imprinted microRNAs and Their RNA Targets

Mammalian genomes contain many imprinted microRNAs. When an imprinted miRNA targets an unimprinted mRNA their interaction may have different fitness consequences for the loci encoding the miRNA and mRNA. In one possible outcome, the mRNA sequence evolves to evade regulation by the miRNA by a simple change of target sequence. Such a response is unavailable if the targeted sequence is strongly constrained by other functions. In these cases, the mRNA evolves to accommodate regulation by the imprinted miRNA. These evolutionary dynamics are illustrated using the examples of the imprinted C19MC cluster of miRNAs in primates and C2MC cluster in mice that are paternally expressed in placentas. The 3′ UTR of PTEN, a gene with growth-related and metabolic functions, appears to be an important target of miRNAs from both clusters.

The Similar Effects of miR-512-3p and miR-519a-2-5p on the Promotion of Hepatocellular Carcinoma: Different Tunes Sung With Equal Skill

Although the therapeutic methods of hepatocellular carcinoma (HCC) have made great advances, the current situation is that HCC is the common malignancy. Our previous bioinformatic study presented that two members of C19MC (mir-512-1 and mir-519a-2) acted as crucial roles in the HCC progression. In this study, we first demonstrated that the miR-512-3p and miR-519a-2-5p, which were spliced from the mir-512-1 and mir-519a-2, were the functional mature miRNAs. Meanwhile, both miR-512-3p and miR-519a-2-5p were significantly upregulated in human HCC samples and HCC cell lines. The miR-512-3p and miR-519a-2-5p promoted the proliferation, invasion, and metastasis in vitro and in vivo. Moreover, the two miRNAs co-targeted the downstream tumor suppressors MAP3K2 and MAP2K4 and subsequently achieved the HCC progression. In the clinical cohort, high expression of miR-512-3p and miR-519a-2-5p acted as two risk factors for HCC recurrence and distinguished patients with poor tumor-free survival after radical resection. The integration of the two miRNAs into the AJCC staging system significantly improved the accuracy for the prediction of HCC recurrence. Our study suggests that miR-512-3p and miR-519a-2-5p have similar effects on the promotion of HCC progression. They can be robust markers for the prediction of HCC recurrence and therapy targets.

Pontine Embryonal Tumor With Multilayered Rosettes: An Autopsy Case Exhibiting Extensive Posttreatment Glial and Neuronal Maturation

Embryonal tumor with multilayered rosettes (ETMR) is a rare and highly aggressive embryonal central nervous system tumor that primarily affects young children. It is characterized by (1) amplification of the C19MC miRNA cluster at 19q13.42 and (2) immunohistochemical tumor cell positivity for LIN28A. We describe the case of a 3-year-old girl who presented with a 2-week history of multiple neurological deficits. Based primarily on imaging findings that revealed a large pontine tumor, biopsy was not performed and the patient was clinically diagnosed with a "diffuse intrinsic pontine glioma." She was subsequently treated with radiation and concurrent adjuvant temozolomide, but unfortunately there was minimal response and the patient died 6 months after diagnosis. Autopsy revealed an ETMR that was confirmed via C19MC fluorescence in situ hybridization and LIN28 immunohistochemistry. Although widespread central nervous system dissemination was observed, large portions of the main pontine mass exhibited evidence of extensive glial and neuronal maturation (ie, differentiation). We consider this tissue "maturation" to have been induced by chemotherapy and radiation. Herein, we discuss the importance of antemortem biopsy of intrinsic pontine tumors and the clinical significance of glial and neuronal maturation post therapy in the context of ETMR.

Placental miRNAs in feto-maternal communication mediated by extracellular vesicles

A complex network composed of at least 1900 microRNA (miRNA) species orchestrates the development and function of the human placenta. These molecules regulate genes and pathways operating major functional processes in trophoblast cells such as proliferation, invasion, differentiation, and metabolism. Nevertheless, the cellular localization and role of most placental miRNAs remain to be determined. The existence of eutherian- (C14MC) and primate-specific miRNA clusters (C19MC), together with human placenta-specific miRNAs, indicate the relevance of these molecules in evolution and diversification of the placenta, including the acquisition of its unique features in humans. They may be related also to diseases that are exclusively present in primates, such as preeclampsia. Changes in the miRNA expression profile have been reported in several placental pathologies. Which miRNAs are involved in the pathomechanism of these diseases or act to maintain placental homeostasis is uncertain. Placenta-derived miRNAs are packed into extracellular vesicles (EVs) and distributed through the maternal circulation to distant organs, where they contribute to adaptations required during pregnancy. Similarly, the placenta also receives molecular information from other tissues to adapt fetoplacental metabolic demands to the maternal energetic supply. These processes can be impaired in pathologic conditions. Therefore, the collection of circulating placental miRNAs constitutes potentially a minimally-invasive approach to assess the fetoplacental status and to diagnose pregnancy diseases. Future therapies may include manipulation of miRNA levels for prevention and treatment of placental complications to protect maternal health and fetal development.

MiR-519d-3p in Trophoblastic Cells: Effects, Targets and Transfer to Allogeneic Immune Cells via Extracellular Vesicles

Members of the placenta-specific miRNA cluster C19MC, including miR-519d, are secreted by fetal trophoblast cells within extracellular vesicles (EVs). Trophoblast-derived EVs can be internalized by the autologous trophoblast and surrounding maternal immune cells, resulting in coordination of cellular responses. The study of functions and targets of placental miRNAs in the donor and recipient cells may contribute to the understanding of the immune tolerance essential in pregnancy. Here, we report that miR-519d-3p levels correlate positively with cell proliferation and negatively with migration in trophoblastic cell lines. Inhibition of miR-519d-3p in JEG-3 cells increases caspase-3 activation and apoptosis. PDCD4 and PTEN are targeted by miR-519d-3p in a cell type-specific manner. Transfection of trophoblastic cell lines with miR-519d mimic results in secretion of EVs containing elevated levels of this miRNA (EV_miR-519d). Autologous cells enhance their proliferation and decrease their migration ability when treated with EV_miR-519d. NK92 cells incorporate EV-delivered miR-519d-3p at higher levels than Jurkat T cells. EV_miR-519d increases the proliferation of Jurkat T cells but decreases that of NK92 cells. Altogether, miR-519d-3p regulates pivotal trophoblast cell functions, can be transferred horizontally via EVs to maternal immune cells and exerts functions therein. Vesicular miRNA transfer from fetal trophoblasts to maternal immune cells may contribute to the immune tolerance in pregnancy.

Hepatic mesenchymal hamartoma and undifferentiated embryonal sarcoma of the liver: a pathologic review

This review highlights two rare entities that are predominantly seen in children: hepatic mesenchymal hamartoma (HMH) and undifferentiated embryonal sarcoma of the liver (UESL). HMH is a benign lesion predominantly seen in the first 2 years of life, while UESL is malignant and usually identified in patients between 6 and 10 years of age. UESL may arise in the background of HMH, and the association has been supported by similar chromosomal aberrations (19q13.4). The diagnosis of both lesions is primarily based on histologic evaluation, as the clinical and radiological features are not always typical. The clinicopathologic characteristics, pathogenesis, differential diagnoses and treatment for both lesions are discussed.

The chromosome 19 microRNA cluster, regulated by promoter hypomethylation, is associated with tumour burden and poor prognosis in patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is still one of the major malignant tumours with poor prognosis. The chromosome 19 microRNA cluster (C19MC) is the largest miRNA cluster, and its functions and regulatory mechanisms remain unclear in HCC. We extracted data from 373 HCC samples and 50 non-tumour samples from The Cancer Genome Atlas database. The differential expression levels and methylation levels of C19MC as well as the correlation between them were analysed. We evaluated the correlation between the expression levels of C19MC and the clinical features. We further performed prognostic analysis for C19MC and analysed the bioinformatic function. C19MC had upregulated expression levels and promoter hypomethylation in HCC. A significant negative correlation between the high expression and low methylation level of C19MC was obtained. In addition, the positive correlation between the expression levels of C19MC and the tumour grade, tumour stage and T-stage is shown. Three miRNAs (mir-512-1, mir-516a-1, mir-519a-2) were negatively associated with overall survival on the basis of the Kaplan-Meier analysis and the 3-miRNA signature was significant for the prognostic assessment of HCC. A bioinformatic enrichment analysis suggested that the target genes of the 3 miRNAs may be associated with mitogen-activated protein kinase pathways related to cancer invasion. In summary, our novel study demonstrated that the hypomethylation of promoters upregulates the expression levels of C19MC and that C19MC may represent a potential new candidate for the diagnosis and therapy of HCC.

Unravelling the Role of Trophoblastic-Derived Extracellular Vesicles in Regulatory T Cell Differentiation

Regulatory T cells (T_reg) are mandatory elements in the maintenance of human pregnancy, but their de novo differentiation has not been completely exposed. HSPE1 chaperone expressing trophoblast cells may have a role in it. Trophoblast-derived extracellular vesicles (EVs), either at the feto–maternal interface or in circulation, target CD4⁺ T cells. We hypothesized that HSPE1-associated trophoblastic cell line (BeWo)-derived EVs are active mediators of T_reg cell differentiation. We proved at first that recombinant HSPE1 promote human T_reg cell differentiation in vitro. Developing a CRISPR-Cas9 based HSPE1 knockout BeWo cell line we could also demonstrate, that EV-associated HSPE1 induces T_reg development. Next-generation sequencing of miRNA cargo of BeWo-EVs characterized the regulatory processes of T_reg polarization. By the use of single-cell transcriptomics analysis, seven T_reg cell subtypes were distinguished and we demonstrated for the first time that the expression level of HSPE1 was T_reg subtype dependent, and CAPG expression is characteristic to memory phenotype of T cells. Our data indicate that HSPE1 and CAPG may be used as markers for identification of T_reg subtypes. Our results suggest, that trophoblastic-derived iEVs-associated HSPE1 and miRNA cargo have an important role in T_reg cell expansion in vitro and HSPE1 is a useful marker of T_reg subtype characterization.

A C19MC-LIN28A-MYCN Oncogenic Circuit Driven by Hijacked Super-enhancers Is a Distinct Therapeutic Vulnerability in ETMRs: A Lethal Brain Tumor

Embryonal tumors with multilayered rosettes (ETMRs) are highly lethal infant brain cancers with characteristic amplification of Chr19q13.41 miRNA cluster (C19MC) and enrichment of pluripotency factor LIN28A. Here we investigated C19MC oncogenic mechanisms and discovered a C19MC-LIN28A-MYCN circuit fueled by multiple complex regulatory loops including an MYCN core transcriptional network and super-enhancers resulting from long-range MYCN DNA interactions and C19MC gene fusions. Our data show that this powerful oncogenic circuit, which entraps an early neural lineage network, is potently abrogated by bromodomain inhibitor JQ1, leading to ETMR cell death.

Embryonal tumor with multilayered rosettes: illustrative case and review of the literature

BACKGROUND

Embryonal tumor with multilayered rosettes (ETMR) is a very rare entity and has seldom been reported. It has been newly defined tumor entity included in the latest update (revised fourth edition) of WHO 2016 Classification of Tumors of the Central Nervous System which portends a uniform dismal prognosis and survival even with the best of multimodality approaches.

ILLUSTRATIVE CASE

This report documents the presentation of a 2-year-old girl with voluminous intracranial ETMR in the right parieto-occipital region. We describe clinical diagnosis, histological aspects, radiological features, and current management of this very aggressive tumor.

CONCLUSION

Pediatric intracranial ETMR is a highly aggressive neoplasm, and it should be considered in the differential diagnosis of pediatric brain tumors.

Distinct communication patterns of trophoblastic miRNA among the maternal-placental-fetal compartments

INTRODUCTION

The placenta produces microRNAs (miRNA) that may traffic to the maternal or fetal compartments and influence the physiology of pregnancy. The trafficking patterns of miRNA expressed from the large human chromosome 19 and chromosome 14 clusters (C19MC and C14MC), remains unclear. We interrogated the cross-sectional landscape of miRNA expression within the human placenta, fetal and maternal plasma to elucidate miRNA trafficking. We hypothesized that C19MC and C14MC miRNAs have similar expression patterns across the maternal-fetal compartments.

METHODS

Placental biopsies, maternal and fetal venous plasma were collected from 25 pregnancies, and RNA was quantified using next generation sequencing. We identified expression and correlations differences among the compartments, and uncovered distinct miRNA expression patterns using consensus clustering.

RESULTS

We found that the placenta exhibits the highest total abundance, average miRNA expression and lowest variance of both C19MC and C14MC miRNAs. The C19MC miRNAs had a comparable expression and variance in fetal and maternal plasma and higher expression in the placenta. In contrast, the C14MC miRNAs had comparable expression between the placenta and fetal plasma, which was higher than the maternal plasma. We also identified 5 distinct groups of trophoblastic miRNAs with different expression patterns in each compartment.

DISCUSSION

This is the first comprehensive analysis of C19MC and C14MC miRNA expression patterns in the human placental, maternal and fetal compartments. Our findings suggest that C14MC miRNAs are produced by both the fetus and placenta, but C19MC miRNAs are produced primarily in the placenta and are trafficked to the fetal and maternal compartments.

Decreased LIN28B in preeclampsia impairs human trophoblast differentiation and migration

Preeclampsia (PE) is a common cause of maternal morbidity, characterized by impaired trophoblast invasion and spiral artery transformation resulting in progressive uteroplacental hypoxia. Given the primary role of LIN28A and LIN28B in modulating cell metabolism, differentiation, and invasion, we hypothesized that LIN28A and/or LIN28B regulates trophoblast differentiation and invasion, and that its dysregulation may contribute to PE. Here we show that LIN28B is expressed ∼1300-fold higher than LIN28A in human term placenta and is the predominant paralog expressed in primary human trophoblast cultures. The expression of LIN28B mRNA and protein levels are significantly reduced in gestational age-matched preeclamptic vs. normal placentas, whereas LIN28A expression is not different. First trimester human placental sections displayed stronger LIN28B immunoreactivity in extravillous (invasive) cytotrophoblasts and syncytial sprouts vs. villous trophoblasts. LIN28B overexpression increased HTR8 cell proliferation, migration, and invasion, whereas LIN28B knockdown in JEG3 cells reduced cell proliferation. Moreover, LIN28B knockdown in JEG3 cells suppressed syncytin 1 (SYN-1), apelin receptor early endogenous ligand (ELABELA), and the chromosome 19 microRNA cluster, and increased mRNA expression of ITGβ4 and TNF-α. Incubation of BeWo and JEG3 cells under hypoxia significantly decreased expression of LIN28B and LIN28A, SYN-1, and ELABELA, whereas TNF-α is increased. These results provide the first evidence that LIN28B is the predominant paralog in human placenta and that decreased LIN28B may play a role in PE by reducing trophoblast invasion and syncytialization, and by promoting inflammation.-Canfield, J., Arlier, S., Mong, E. F., Lockhart, J., VanWye, J., Guzeloglu-Kayisli, O., Schatz, F., Magness, R. R., Lockwood, C. J., Tsibris, J. C. M., Kayisli, U. A., Totary-Jain, H. Decreased LIN28B in preeclampsia impairs human trophoblast differentiation and migration.

Modulation of LIN28B/Let-7 Signaling by Propranolol Contributes to Infantile Hemangioma Involution

OBJECTIVE

Infantile hemangiomas (IHs) are the most common benign vascular neoplasms of infancy, characterized by a rapid growth phase followed by a spontaneous involution, or triggered by propranolol treatment by poorly understood mechanisms. LIN28/let-7 axis plays a central role in the regulation of stem cell self-renewal and tumorigenesis. However, the role of LIN28B/let-7 signaling in IH pathogenesis has not yet been elucidated.

APPROACH AND RESULTS

LIN28B is highly expressed in proliferative IH and is less expressed in involuted and in propranolol-treated IH samples as measured by immunofluorescence staining and quantitative RT-PCR. Small RNA sequencing analysis of IH samples revealed a decrease in microRNAs that target LIN28B, including let-7, and an increase in microRNAs in the mir-498(46) cistron. Overexpression of LIN28B in HEK293 cells induced the expression of miR-516b in the mir-498(46) cistron. Propranolol treatment of induced pluripotent stem cells, which express mir-498(46) endogenously, reduced the expression of both LIN28B and mir-498(46) and increased the expression of let-7. Furthermore, propranolol treatment reduced the proliferation of induced pluripotent stem cells and induced epithelial-mesenchymal transition.

CONCLUSIONS

This work uncovers the role of the LIN28B/let-7 switch in IH pathogenesis and provides a novel mechanism by which propranolol induces IH involution. Furthermore, it provides therapeutic implications for cancers in which the LIN28/let-7 pathway is imbalanced.

Embryonal tumor with multilayered rosettes, C19MC-altered: Report of an extremely rare malignant pediatric central nervous system neoplasm

The 2016 update of the WHO Classification of Tumours of the Central Nervous System has redefined a number of tumors. Embryonal tumor with multilayered rosettes, C19MC-altered is one such tumor entity which has been newly defined on the basis of a characteristic molecular alteration. We report, to our knowledge, the first case of this rare pediatric brain neoplasm in the Pakistani population. An 8-month-old girl was presented with vomiting and left-sided ptosis, and magnetic resonance imaging scan showed a cerebellar tumor. Histologically, a highly cellular population of primitive cells was seen alternating with hypocellular neuropil-rich regions containing multilayered true rosettes and cells with glial and neuronal differentiation. Amplification of 19q13. 42 chromosome region on fluorescence in situ hybridization analysis confirmed the diagnosis. Post-operative radiological examination revealed widespread central nervous system involvement. Adjuvant treatment was not offered due to complications. Patient expired a week after diagnosis.

MicroRNAs in parathyroid physiopathology

Parathyroid glands regulate calcium homeostasis through synthesis and secretion of parathormone (PTH). They sense the extracellular calcium concentration through the G-protein coupled calcium sensing receptor (CASR) and release PTH in order to preserve calcium concentration in the physiological range. Tumors of the parathyroid glands are common endocrine neoplasia associated with primary or secondary/tertiary hyperparathyroidisms. Small non-coding RNAs are regulators of gene expression able to modulate hormone synthesis, hormone release and endocrine cell proliferation. In this scenario, microRNA (miRNA) expression profiles have been investigated in parathyroid tumors, while miRNAs are involved in hypocalcemia and uremia-induced PTH release from normal parathyroid cells. Here we reviewed data about the role of miRNAs in the regulation of: 1) PTH synthesis and secretion; 2) CASR expression; 3) parathyroid cell tumorigenesis. Though studies about miRNAs in parathyroid gland pathophysiology are limited, they contribute in elucidating regulatory pathways involved in PTH release and parathyroid cell tumorigenesis.

miR-524-5p of the primate-specific C19MC miRNA cluster targets TP53IPN1- and EMT-associated genes to regulate cellular reprogramming

Background

Introduction of the transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is able to ‘reprogram’ somatic cells to become induced pluripotent stem cells (iPSCs). Several microRNAs (miRNAs) are known to enhance reprogramming efficiency when co-expressed with the OSKM factors. The primate-specific chromosome 19 miRNA cluster (C19MC) is essential in primate reproduction, development, and differentiation. miR-524-5p, a C19MC member, is highly homologous to the reprogramming miR-520d-5p; we also reported that miR-524-5p was expressed in iPSCs but not mesenchymal stem cells (MSCs). This study aimed to elucidate possible contributions of miR-524-5p to the reprogramming process.

Methods

A miR-524-5p precursor was introduced into human fibroblast HFF-1 in the presence of OSKM, and the relative number of embryonic stem cell (ESC)-like colonies that stained positively with alkaline phosphatase (AP) and Nanog were quantified to determine reprogramming efficiency. A miR-524-5p mimic was transfected to MSCs to investigate the effects of miR-524-5p on TP53INP1, ZEB2, and SMAD4 expression by real-time polymerase chain reaction (PCR) and Western blot. Direct gene targeting was confirmed by luciferase activity. A phylogenetic tree of TP53INP1 was constructed by the Clustal method. Contribution of miR-524-5p to cell proliferation and apoptosis was examined by cell counts, BrdU, MTT, and cell death assays, and pluripotency gene expression by real-time PCR.

Results

Co-expressing the miR-524 precursor with OSKM resulted in a two-fold significant increase in the number of AP- and Nanog-positive ESC-like colonies, indicating a role for miR-524-5p in reprogramming. The putative target, TP53INP1, showed an inverse expression relationship with miR-524-5p; direct TP53INP1 targeting was confirmed in luciferase assays. miR-524-5p-induced TP53INP1 downregulation enhanced cell proliferation, suppressed apoptosis, and upregulated the expression of pluripotency genes, all of which are critical early events of the reprogramming process. Interestingly, the TP53INP1 gene may have co-evolved late with the primate-specific miR-524-5p. miR-524-5p also promoted mesenchymal-to-epithelial transition (MET), a required initial event of reprogramming, by directly targeting the epithelial-to-mesenchymal transition (EMT)-related genes, ZEB2 and SMAD4.

Conclusions

Via targeting TP53INP1, ZEB2, and SMAD4, miR-524-5p contributes to the early stage of inducing pluripotency by promoting cell proliferation, inhibiting apoptosis, upregulating expression of pluripotency genes, and enhancing MET. Other C19MC miRNAs may have similar reprogramming functions.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0666-3) contains supplementary material, which is available to authorized users.

Expression and trafficking of placental microRNAs at the feto-maternal interface

During pregnancy, placental trophoblasts at the feto-maternal interface produce a broad repertoire of microRNA (miRNA) species. These species include miRNA from the primate-specific chromosome 19 miRNA cluster (C19MC), which is expressed nearly exclusively in the placenta. Trafficking of these miRNAs among the maternal, placental, and fetal compartments is unknown. To determine miRNA expression and trafficking patterns during pregnancy, we sequenced miRNAs in triads of human placenta and of maternal and fetal blood and found large subject-to-subject variability, with C19MC exhibiting compartment-specific expression. We therefore created humanized mice that transgenically express the entire 160-kb human C19MC locus or lentivirally express C19MC miRNA members selectively in the placenta. C19MC transgenic mice expressed a low level of C19MC miRNAs in diverse organs. When pregnant, female C19MC mice exhibited a strikingly elevated (>40-fold) expression of C19MC miRNA in the placenta, compared with other organs, that resembled C19MC miRNAs patterns in humans. Our mouse models showed that placental miRNA traffic primarily to the maternal circulation and that maternal miRNA can traffic to the placenta and even into the fetal compartment. These findings define an extraordinary means of nonhormonal, miRNA-based communication between the placenta and feto-maternal compartments.-Chang, G., Mouillet, J.-F., Mishima, T., Chu, T., Sadovsky, E., Coyne, C. B., Parks, W. T., Surti, U., Sadovsky, Y. Expression and trafficking of placental microRNAs at the feto-maternal interface.

Selective activation of miRNAs of the primate-specific chromosome 19 miRNA cluster (C19MC) in cancer and stem cells and possible contribution to regulation of apoptosis

Background

The human chromosome 19 miRNA cluster (C19MC) of 43 genes is a primate-specific miRNA cluster that may have biological significance in the genetic complexity of the primate. Despite previous reports on individual C19MC miRNA expression in cancer and stem cells, systematic studies on C19MC miRNA expression and biological functions are lacking.

Results

Cluster-wide C19MC miRNA expression profiling by microarray analysis showed wholesome C19MC activation in embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs). However, in multipotent adipose-derived mesenchymal stem cells (MSCs) and a unipotent human white pre-adipocyte cell line, only selected C19MC miRNAs were expressed. MiRNA copy number analysis also showed selective C19MC expression in cancer cells with expression patterns highly similar to those in MSCs, suggesting similar miRNA regulatory mechanisms in these cells. Selective miRNA expression also suggests complex transcriptional mechanism(s) regulating C19MC expression under specific cellular and pathological conditions. Bioinformatics analysis showed that sixteen of the C19MC miRNAs share the same “AAGUGC” seed sequence with members of the miR-302/-372 family, which are known cellular reprogramming factors. In particular, C19MC-AAGUGC-miRNAs with the nucleotides 2-7 canonical seed position as in miR-302/-372 miRNAs, may play similar roles as miR-302/-372 in induced pluripotency. A biased 3p-arm selection of the C19MC-AAGUGC-miRNAs was observed indicating that targets of the 3p species of these miRNAs may be biologically significant in regulating stemness. Furthermore, bioinformatics analysis of the putative targets of the C19MC-AAGUGC-miRNAs predicted significant involvement of signaling pathways in reprogramming, many of which contribute to promoting apoptosis by indirect activation of the pro-apoptotic proteins BAK/BAX via suppression of genes of the cell survival pathways, or by enhancing caspase-8 activation through targeting inhibitors of TRAIL-inducing apoptosis.

Conclusions

This work demonstrated selective C19MC expression in MSCs and cancer cells, and, through miRNA profiling and bioinformatics analysis, predicted C19MC modulation of apoptosis in induced pluripotency and tumorigenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12929-017-0326-z) contains supplementary material, which is available to authorized users.

The function of miR-519d in cell migration, invasion, and proliferation suggests a role in early placentation

The processes of proliferation, migration, and invasion of extravillous trophoblasts are critical for placental implantation and early development, and directly influence pregnancy outcome. Dysregulation of these processes has been associated with placental dysfunction, implicated in clinical conditions such as preeclampsia and placental accreta. Among diverse microRNA (miRNA) species that are expressed in placental trophoblasts, members of the chromosome 19 miRNA cluster (C19MC) stand out in their nearly exclusive expression in the placenta. Recent research on the function of C19MC miRNAs in normal cell physiology and during tumorigenesis identified one C19MC member, miR-519d, as a regulator of cell migration, invasion, and interaction with the extracellular matrix. In this review, we focus on the function of miR-519d in placental trophoblasts, where miR-519d regulates cell migration and invasion, and its aberrant expression is associated with preeclampsia. In cancer, the function of miR-519d as an oncomiR or a tumor-suppressor is dependent upon the tumor type. Further research on the biological function and regulation of miR-519d may illuminate previously unknown mechanisms that control cell migration and invasion.

Isolation of human trophoblastic extracellular vesicles and characterization of their cargo and antiviral activity

INTRODUCTION

Primary human trophoblasts release a repertoire of extracellular vesicles (EVs). Among them are nano-sized exosomes, which we found to suppress the replication of a wide range of diverse viruses. These exosomes contain trophoblastic microRNAs (miRNAs) that are expressed from the chromosome 19 miRNA cluster and exhibit antiviral properties. Here, we report our investigation of the cargo of placental EVs, focusing on the composition and the antiviral properties of exosomes, microvesicles, and apoptotic blebs.

METHODS

We isolated EVs using ultracentrifugation and defined their purity using immunoblotting, electron microscopy, and nanoparticle tracking. We used liquid chromatography-electrospray ionization-mass spectrometry, protein mass spectrometry, and miRNA TaqMan card PCR to examine the phospholipids, proteins, and miRNA cargo of trophoblastic EVs and an in vitro viral infection assay to assess the antiviral properties of EVs.

RESULTS

We found that all three EV types contain a comparable repertoire of miRNA. Interestingly, trophoblastic exosomes harbor a protein and phospholipid profile that is distinct from that of microvesicles or apoptotic blebs. Functionally, trophoblastic exosomes exhibit the highest antiviral activity among the EVs. Consistently, plasma exosomes derived from pregnant women recapitulate the antiviral effect of trophoblastic exosomes derived from in vitro cultures of primary human trophoblasts.

DISCUSSION

When compared to other trophoblastic EVs, exosomes exhibit a unique repertoire of proteins and phospholipids, but not miRNAs, and a potent viral activity. Our work suggests that human trophoblastic EVs may play a key role in maternal-placental-fetal communication.

Expression of microRNAs of C19MC in Different Histological Types of Testicular Germ Cell Tumour

BACKGROUND

Testicular germ cell tumours (TGCTs) are the most common tumours in men aged from 20 to 40 years, with a steadily increasing incidence. This study aimed to characterize the expression of the miRNA cluster C19MC in TGCT and to evaluate the suitability of a C19MC miRNA as a serum biomarker.

MATERIALS AND METHODS

By quantitative reverse transcription PCR, we measured the expression of miR-517a-3p, miR-519a-3p, and miR-519c 3p in tissue samples of 25 TGCTs and the level of miR-517a-3p in serum samples obtained pre- and postoperatively from the same patients.

RESULTS

We detected a significantly higher expression of C19MC miRNAs in non-seminomas than in seminomas and in clinical stages 2 and 3 than in stage 1 in both tissue and serum samples.

CONCLUSION

miRNAs of C19MC are overexpressed in more aggressive types of TGCT, suggesting they contribute to malignancy. Furthermore, they might serve as serum biomarkers for these types of TGCT.

The Placenta as a Barrier to Viral Infections

Throughout pregnancy, the placenta acts as a physical and immunological barrier against the hematogenous transmission of viruses from mother to fetus. Despite this, very little is known regarding the specific mechanisms by which the placenta shields the developing fetus from viral infections or about the strategies utilized by select viruses to bypass and/or weaken the placental barrier. In this review, we summarize studies regarding virus-host interactions at the placental interface and explore key areas for future investigation. We focus our review on placental trophoblasts, which form the barrier between maternal and fetal circulations and thus govern the cross talk between the maternal and fetal microenvironments.

MicroRNAs in placental health and disease

MicroRNAs (miRNAs) constitute a large family of small noncoding RNAs that are encoded by the genomes of most organisms. They regulate gene expression through posttranscriptional mechanisms to attenuate protein output in various genetic networks. The discovery of miRNAs has transformed our understanding of gene regulation and sparked intense efforts intended to harness their potential as diagnostic markers and therapeutic tools. Over the last decade, a flurry of studies has shed light on placental miRNAs but has also raised many questions regarding the scope of their biologic action. Moreover, the recognition that miRNAs of placental origin are released continually in the maternal circulation throughout pregnancy suggested that circulating miRNAs might serve as biomarkers for placental function during pregnancy. Although this generated much enthusiasm, recently recognized challenges have delayed the application of miRNA-based biomarkers and therapeutics in clinical practice. In this review, we summarize key findings in the field and discuss current knowledge related to miRNAs in the context of placental biology.

DNMTs as potential therapeutic targets in high-risk pediatric embryonal brain tumors

Malignant brain tumors, which are the leading cause of cancer-related morbidity and mortality in children, span a wide spectrum of diseases with distinct clinical phenotypes but may share remarkably similar morphologic features. Until recently, few molecular markers of childhood brain tumors have been identified, which has limited therapeutic advances. Recent global genomic studies have enabled robust molecular classification of childhood brain tumors and the identification and consolidation of rare, seemingly disparate clinical entities. It is now increasingly evident that deregulation of epigenetic processes contributes substantially to heterogeneity in tumor phenotypes and comprise significant drivers of cancer initiation and progression. Specifically, DNA hypermethylation and silencing of critical tumor suppressor genes by DNA methyltransferases (DNMT) has emerged as an important and fundamental mechanism in brain tumor pathogenesis. These observations have been underscored by the recent discovery of TTYH1-C19MC gene fusions in an aggressive pediatric embryonal brain tumor, which results in deregulation and increased expression of a neural-specific DNMT3B isoform in C19MC-associated brain tumors. Our observations that pharmacological inhibitors of DNMTs and histone deacetylases significantly inhibit growth of cells derived from C19MC-associated tumors indicate targeting of epigenomic modifiers as a novel therapeutic approach for these highly treatment-resistant tumors.

A novel C19MC amplified cell line links Lin28/let-7 to mTOR signaling in embryonal tumor with multilayered rosettes

BACKGROUND

Embryonal tumor with multilayered rosettes (ETMR) is an aggressive central nervous system primitive neuroectodermal tumor (CNS-PNET) variant. ETMRs have distinctive histology, amplification of the chromosome 19 microRNA cluster (C19MC) at chr19q13.41-42, expression of the RNA binding protein Lin28, and dismal prognosis. Functional and therapeutic studies of ETMR have been limited by a lack of model systems.

METHODS

We have established a first cell line, BT183, from a case of ETMR and characterized its molecular and cellular features. LIN28 knockdown was performed in BT183 to examine the potential role of Lin28 in regulating signaling pathway gene expression in ETMR. Cell line findings were corroborated with immunohistochemical studies in ETMR tissues. A drug screen of 73 compounds was performed to identify potential therapeutic targets.

RESULTS

The BT183 line maintains C19MC amplification, expresses C19MC-encoded microRNAs, and is tumor initiating. ETMRs, including BT183, have high LIN28 expression and low let-7 miRNA expression, and show evidence of mTOR pathway activation. LIN28 knockdown increases let-7 expression and decreases expression of IGF/PI3K/mTOR pathway components. Pharmacologic inhibition of the mTOR pathway reduces BT183 cell viability.

CONCLUSIONS

BT183 retains key genetic and histologic features of ETMR. In ETMR, Lin28 is not only a diagnostic marker but also a regulator of genes involved in growth and metabolism. Our findings indicate that inhibitors of the IGF/PI3K/mTOR pathway may be promising novel therapies for these fatal embryonal tumors. As the first patient-derived cell line of these rare tumors, BT183 is an important, unique reagent for investigating ETMR biology and therapeutics.

Review: placenta-specific microRNAs in exosomes - good things come in nano-packages

MicroRNAs (miRNAs) are small noncoding RNA gene products that commonly regulate mRNA expression by repression of translation and/or transcript decay. Whereas common and unique types of miRNAs are expressed by the placenta during pregnancy, the functions of most placental miRNA species are unknown. In addition to their intracellular silencing function, miRNAs are also released to the extracellular space and systemic circulation, where they can potentially target cells to regulate mRNA and protein expression, providing a non-hormonal means of intercellular communication that contributes to tissue homeostasis and disease pathophysiology. This review centers on extracellular miRNAs that originate in trophoblasts and that could mediate crosstalk between the feto-placental unit and the mother during pregnancy. We specifically detail the function of miRNAs from the primate-specific chromosome 19 miRNA cluster. These miRNAs are highly expressed in human placentas and in the serum of pregnant women. They are also packaged into extracellular vesicles of diverse sizes, including exosomes, and endow non-trophoblastic cells with resistance to a variety of viruses.

Autophagy as a mechanism of antiviral defense at the maternal-fetal interface

Mechanisms to protect against viral infections are crucial during pregnancy as maternal-fetal transmission can have serious pathological outcomes, including fetal infection and its sequelae, such as growth restriction, birth defects, and/or fetal death. The trophoblast forms the interface between the feto-placental unit and the maternal blood, and is therefore a critical physical and immunological barrier to restrict the spread of pathogens into the fetal microenvironment. Recently, we found that primary human placental trophoblast (PHT) cells are highly resistant to infection by diverse viruses. In this study, we also found that conditioned medium from PHT cell cultures transferred viral resistance to nonplacental recipient cells, suggesting that a component secreted by trophoblasts and present within the conditioned medium is responsible for this antiviral effect. We found that specific miRNAs from a unique primate- and placental-specific locus?the C19MC (chromosome 19 miRNA cluster)?are packaged within exosomes produced by PHT cells and confer viral resistance in nonplacental recipient cells. In addition to conveying viral resistance, we found that PHT-derived exosomes and select miRNA members of the C19MC family strongly induce autophagy, which is involved in recipient cell viral resistance. Our findings establish an exciting and novel mechanism by which placental trophoblasts exploit exosome-dependent transfer of placental-specific miRNAs to influence autophagic induction and antiviral immunity at the maternal?fetal interface.

Human placental trophoblasts confer viral resistance to recipient cells

Placental trophoblasts form the interface between the fetal and maternal environments and serve to limit the maternal-fetal spread of viruses. Here we show that cultured primary human placental trophoblasts are highly resistant to infection by a number of viruses and, importantly, confer this resistance to nonplacental recipient cells by exosome-mediated delivery of specific microRNAs (miRNAs). We show that miRNA members of the chromosome 19 miRNA cluster, which are almost exclusively expressed in the human placenta, are packaged within trophoblast-derived exosomes and attenuate viral replication in recipient cells by the induction of autophagy. Together, our findings identify an unprecedented paracrine and/or systemic function of placental trophoblasts that uses exosome-mediated transfer of a unique set of placental-specific effector miRNAs to directly communicate with placental or maternal target cells and regulate their immunity to viral infections.