microRNAs regulate β-catenin of the Wnt signaling pathway in early sea urchin development

microRNA-1 regulates sea urchin skeletogenesis by directly targeting skeletogenic genes and modulating components of signaling pathways

microRNAs are evolutionarily conserved non-coding RNAs that direct post-transcriptional regulation of target transcripts. In vertebrates, microRNA-1 (miR-1) is expressed in muscle and has been found to play critical regulatory roles in vertebrate angiogenesis, a process that has been proposed to be analogous to sea urchin skeletogenesis. Results indicate that both miR-1 inhibitor and miR-1 mimic-injected larvae have significantly less F-actin enriched circumpharyngeal muscle fibers and fewer gut contractions. In addition, miR-1 regulates the positioning of skeletogenic primary mesenchyme cells (PMCs) and skeletogenesis of the sea urchin embryo. Interestingly, the gain-of-function of miR-1 leads to more severe PMC patterning and skeletal branching defects than its loss-of-function. The results suggest that miR-1 directly suppresses Ets1/2, Tbr, and VegfR7 of the skeletogenic gene regulatory network, and Nodal, and Wnt1 signaling components. This study identifies potential targets of miR-1 that impacts skeletogenesis and muscle formation and contributes to a deeper understanding of miR-1's function during development.

Expression of circulating oar-miR-485-5p and oar-miR-493-5p during the estrous cycle and early pregnancy in ovine plasma

In the current study, we aimed to assess the expression levels of two circulating microRNAs (miRNA) (oar-miR-485-5p and oar-miR-493-5p) in the ovine plasma during the peri-implantation. After mating, we collected the plasma samples from a total of 8 ewes on day 22 of pregnancy (P22; n = 4) and day 22 of the estrous cycle (C22; n=4). We used mature miRNA sequences for oar-miR-485-5p and oar-miR-493-5p out of one hundred fifty, which were retrieved from our microarray results of previous study. We showed that the miRNA expression of oar-miR-485-5p and oar-miR-493-5p were upregulated in P22 (P<0.05) when compared to C22. Those two miRNAs targeted 311 target genes in the peri-implantation period of pregnancy. Furthermore, we revealed 151 GO/pathway terms in biological process (BP) and 25 GO/pathway terms in molecular function (MF), while we demonstrated 13 GO/pathway terms in cellular component (CC). We revealed three hub genes as interleukin 2 (IL2), interleukin 18 (IL18), and C-X-C Motif Chemokine Ligand 10 (CXCL10). In conclusion, both miR-485-5p and oar-miR-493-5p have the potential to be a biomarker to understand peri-implantation of the ovine pregnancy in the aspect of pregnancy-reflected changes in maternal plasma.

Comparative Analysis of Bivalve and Sea Urchin Genetics and Development: Investigating the Dichotomy in Bilateria

This comprehensive review presents a comparative analysis of early embryogenesis in Protostomia and Deuterostomia, the first of which exhibit a mosaic pattern of development, where cells are fated deterministically, while Deuterostomia display a regulatory pattern of development, where the fate of cells is indeterminate. Despite these fundamental differences, there are common transcriptional mechanisms that underline their evolutionary linkages, particularly in the field of functional genomics. By elucidating both conserved and unique regulatory strategies, this review provides essential insights into the comparative embryology and developmental dynamics of these groups. The objective of this review is to clarify the shared and distinctive characteristics of transcriptional regulatory mechanisms. This will contribute to the extensive areas of functional genomics, evolutionary biology and developmental biology, and possibly lay the foundation for future research and discussion on this seminal topic.

microRNA-124 directly suppresses Nodal and Notch to regulate mesodermal development

MicroRNAs regulate gene expression post-transcriptionally by destabilizing and/or inhibiting translation of target mRNAs in animal cells. MicroRNA-124 (miR-124) has been examined mostly in the context of neurogenesis. This study discovers a novel role of miR-124 in regulating mesodermal cell differentiation in the sea urchin embryo. The expression of miR-124 is first detectable at 12hours post fertilization at the early blastula stage, during endomesodermal specification. Mesodermally-derived immune cells come from the same progenitor cells that give rise to blastocoelar cells (BCs) and pigment cells (PCs) that must make a binary fate decision. We determined that miR-124 directly represses Nodal and Notch to regulate BC and PC differentiation. miR-124 inhibition does not impact the dorsal-ventral axis formation, but result in a significant increase in number of cells expressing BC-specific transcription factors (TFs) and a concurrent reduction of differentiated PCs. In general, removing miR-124's suppression of Nodal phenocopies miR124 inhibition. Interestingly, removing miR-124's suppression of Notch leads to an increased number of both BCs and PCs, with a subset of hybrid cells that express both BC- and PC-specific TFs in the larvae. Removal of miR-124's suppression of Notch not only affects differentiation of both BCs and PCs, but also induces cell proliferation of these cells during the first wave of Notch signaling. This study demonstrates that post-transcriptional regulation by miR-124 impacts differentiation of BCs and PCs by regulating the Nodal and Notch signaling pathways.

RNA localization to the mitotic spindle is essential for early development and is regulated by kinesin-1 and dynein

Mitosis is a fundamental and highly regulated process that acts to faithfully segregate chromosomes into two identical daughter cells. Localization of gene transcripts involved in mitosis to the mitotic spindle might be an evolutionarily conserved mechanism to ensure that mitosis occurs in a timely manner. We identified many RNA transcripts that encode proteins involved in mitosis localized at the mitotic spindles in dividing sea urchin embryos and mammalian cells. Disruption of microtubule polymerization, kinesin-1 or dynein results in lack of spindle localization of these transcripts in the sea urchin embryo. Furthermore, results indicate that the cytoplasmic polyadenylation element (CPE) within the 3'UTR of the Aurora B transcript, a recognition sequence for CPEB, is essential for RNA localization to the mitotic spindle in the sea urchin embryo. Blocking this sequence results in arrested development during early cleavage stages, suggesting that RNA localization to the mitotic spindle might be a regulatory mechanism of cell division that is important for early development.

microRNA-124 regulates Notch and NeuroD1 to mediate transition states of neuronal development

MicroRNAs regulate gene expression by destabilizing target mRNA and/or inhibiting translation in animal cells. The ability to mechanistically dissect miR-124's function during specification, differentiation, and maturation of neurons during development within a single system has not been accomplished. Using the sea urchin embryo, we take advantage of the manipulability of the embryo and its well-documented gene regulatory networks (GRNs). We incorporated NeuroD1 as part of the sea urchin neuronal GRN and determined that miR-124 inhibition resulted in aberrant gut contractions, swimming velocity, and neuronal development. Inhibition of miR-124 resulted in an increased number of cells expressing transcription factors (TFs) associated with progenitor neurons and a concurrent decrease of mature and functional neurons. Results revealed that in the early blastula/gastrula stages, miR-124 regulates undefined factors during neuronal specification and differentiation. In the late gastrula/larval stages, miR-124 regulates Notch and NeuroD1 during the transition between neuronal differentiation and maturation. Overall, we have improved the neuronal GRN and identified miR-124 to play a prolific role in regulating various transitions of neuronal development.

Micromanaging pattern formation: miRNA regulation of signaling systems in vertebrate development

Early embryogenesis requires the establishment of fields of progenitor cells with distinct molecular signatures. A balance of intrinsic and extrinsic cues determines the boundaries of embryonic territories and pushes progenitor cells toward different fates. This process involves multiple layers of regulation, including signaling systems, transcriptional networks, and post-transcriptional control. In recent years, microRNAs (miRNAs) have emerged as undisputed regulators of developmental processes. Here, we discuss how miRNAs regulate pattern formation during vertebrate embryogenesis. We survey how miRNAs modulate the activity of signaling pathways to optimize transcriptional responses in embryonic cells. We also examine how localized RNA interference can generate spatial complexity during early development. Unraveling the complex crosstalk between miRNAs, signaling systems and cell fate decisions will be crucial for our understanding of developmental outcomes and disease.

Circulating miRNAs in maternal plasma as potential biomarkers of early pregnancy in sheep

MicroRNA (miRNA) plays an important role in the control of gene expression and is implied in many biological functions, including embryo implantation and development. The aim was to assess plasma miRNA profiles during the peri-implantation and ascertain potential candidate miRNA markers for early pregnancy diagnosis in ovine plasma. The plasma samples were obtained from a total of 24 ewes on days 12 (pre-implantation; P12, n = 4), 16 (implantation; P16, n = 4) and 22 (post-implantation; P22, n = 4) after mating, and on their corresponding days of 12 (Pre-C; C12, n = 4), 16 (Imp-C; C16, n = 4) and 22 (Post-C; C22, n = 4) of the estrous cycle. The miRNA profiles in plasma were assessed by microarray technology. We detected the presence of 60 ovine-specific miRNAs in plasma samples. Of these miRNAs, 22 demonstrated a differential expression pattern, especially between the estrous cycle and early pregnancy, and targeted 521 genes. Two miRNAs (oar-miR-218a and oar-miR-1185-3p) were confirmed using RT-qPCR in the ovine plasma samples. Protein-protein interaction (PPI) network of target genes established six functional modules, of which modules 1 and 3 were enriched in the common GO terms, such as inflammatory response, defense response, and regulation of immune response. In contrast, module 2 was enriched in the developmental process involved in reproduction, embryo development, embryonic morphogenesis, and regulation of the developmental process. The results indicate that miRNAs profiles of plasma seemed to be modulated during the peri-implantation stage of pregnancy in ewes. Circulating miRNAs could be promising candidates for diagnosis in early ovine pregnancy.

microRNA-31 regulates skeletogenesis by direct suppression of Eve and Wnt1

microRNAs (miRNAs) play a critical role in a variety of biological processes, including embryogenesis and the physiological functions of cells. Evolutionarily conserved microRNA-31 (miR-31) has been found to be involved in cancer, bone formation, and lymphatic development. We previously discovered that, in the sea urchin, miR-31 knockdown (KD) embryos have shortened dorsoventral connecting rods, mispatterned skeletogenic primary mesenchyme cells (PMCs) and shifted and expanded Vegf3 expression domain. Vegf3 itself does not contain miR-31 binding sites; however, we identified its upstream regulators Eve and Wnt1 to be directly suppressed by miR-31. Removal of miR-31's suppression of Eve and Wnt1 resulted in skeletal and PMC patterning defects, similar to miR-31 KD phenotypes. Additionally, removal of miR-31's suppression of Eve and Wnt1 results in an expansion and anterior shift in expression of Veg1 ectodermal genes, including Vegf3 in the blastulae. This indicates that miR-31 indirectly regulates Vegf3 expression through directly suppressing Eve and Wnt1. Furthermore, removing miR-31 suppression of Eve is sufficient to cause skeletogenic defects, revealing a novel regulatory role of Eve in skeletogenesis and PMC patterning. Overall, this study provides a proposed molecular mechanism of miR-31's regulation of skeletogenesis and PMC patterning through its cross-regulation of a Wnt signaling ligand and a transcription factor of the endodermal and ectodermal gene regulatory network.

MicroRNA-497-5p attenuates IL-1β-induced cartilage matrix degradation in chondrocytes via Wnt/β-catenin signal pathway

Osteoarthritis (OA) is a degenerative joint disease. Degradation of extracellular matrix (ECM) in chondrocytes is closely related to joint destruction in OA progression. MicroRNAs (miRNAs) have been reported to play important roles in progression of OA. However, the roles of miR-497-5p in OA process and its underlying mechanism remain not been well established. Chondrocytes were obtained from articular cartilage and stimulated with IL-1β. The expression of miR-497-5p and Wnt3a was detected by qRT-PCR. Western blot analysis was performed to measure the proteins of Wnt3a, collagen II, aggrecan matrix metalloproteinase (MMP) 13 and ADAMTS4. Cell apoptosis was detected by flow cytometry. The putative binding sites of miR-497-5p and Wnt3a were predicted by Targetscan and verified through luciferase report assay. We found that miR-497-5p expression was reduced and Wnt3a expression was enhanced in OA cartilage and IL-1β-stimulated chondrocytes. Moreover, Wnt3a was a direct target of miR-497-5p, and expression of miR-497-5p was negatively correlated with Wnt3a level in OA cartilage. Furthermore, overexpression of miR-497-5p prominently increased the expression of cartilage matrix molecules collagen II and aggrecan, and reduced the expression of matrix-degrading enzymes MMP13 and ADAMTS4 while overexpression of Wnt3a reversed these effects, whereas addition of DKK-1attenuated the Wnt3a-mediated functions in IL-1β-stimulated chondrocytes. In conclusion, miR-497-5p attenuated IL-1β-induced cartilage matrix degradation in chondrocytes via Wnt/β-catenin signal pathway, providing a potential therapeutic target for treatment of OA.

Distinct transcriptional regulation of Nanos2 in the germ line and soma by the Wnt and delta/notch pathways

Specification of the primordial germ cells (PGCs) is essential for sexually reproducing animals. Although the mechanisms of PGC specification are diverse between organisms, the RNA binding protein Nanos is consistently required in the germ line in all species tested. How Nanos is selectively expressed in the germ line, however, remains largely elusive. We report that in sea urchin embryos, the early expression of Nanos2 in the PGCs requires the maternal Wnt pathway. During gastrulation, however, Nanos2 expression expands into adjacent somatic mesodermal cells and this secondary Nanos expression instead requires Delta/Notch signaling through the forkhead family member FoxY. Each of these transcriptional regulators were tested by chromatin immunoprecipitation analysis and found to directly interact with a DNA locus upstream of Nanos2. Given the conserved importance of Nanos in germ line specification, and the derived character of the micromeres and small micromeres in the sea urchin, we propose that the ancestral mechanism of Nanos2 expression in echinoderms was by induction in mesodermal cells during gastrulation.

Roles of β-catenin, TCF-4, and survivin in nasopharyngeal carcinoma: correlation with clinicopathological features and prognostic significance

Background

Nasopharyngeal carcinoma (NPC) is a common malignant tumor of the head and neck region with poorly understood progression and prognosis. The present study aims at exploring whether the expression of β-catenin, TCF-4, and survivin affects clinicopathological features and prognostic significance in NPC.

Methods

We enrolled 164 patients with NPC and 70 patients with chronic nasopharyngitis (CNP) in this study. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC) were conducted to evaluate the expression of β-catenin, TCF-4, and survivin. Spearman’s rank correlation analysis and Pearson correlation analysis were used to measure the correlation of β-catenin, TCF-4, and survivin. Risk factors for prognosis and survival conditions of NPC patients were analyzed by Cox proportional hazards model and Kaplan–Meier curves.

Results

The results obtained revealed that mRNA and protein expression of β-catenin, TCF-4, and survivin was higher in NPC tissues than in CNP tissues. Positive correlations amongst β-catenin, TCF-4, and survivin were identified by Spearman’s rank correlation analysis and Pearson correlation analysis. There was a significant correlation in expression of β-catenin, TCF-4, and survivin with EBV DNA, EBV-VCA-IgA, EBV-EA-IgA, T stage, N stage, and clinicopathological stages. Lower overall survival (OS), distant metastasis-free survival (DMFS), local recurrence-free survival (LRFS), and disease-free survival (DFS) rates were detected in NPC patients with positive expression of β-catenin, TCF-4, and survivin, in contrast to those with negative expression. Cox proportional hazards model demonstrated that β-catenin, TCF-4, and survivin protein positive expression were independent risk factors for OS and DFS of NPC prognosis; there was an evident correlation between clinicopathological stages, TCF-4, and EBV-EA-IgA and OS, DMFS, LRFS, and DFS of NPC.

Conclusions

The aforementioned results indicate that β-catenin, TCF-4, and survivin proteins are highly expressed in NPC, which can be used as factors to predict the malignancy of NPC. In addition, positive expression of β-catenin, TCF-4, and survivin are potential risk factors that lead to an unfavorable prognosis of OS and DFS in NPC patients.

Analysis of microRNA functions

MicroRNAs (miRNAs) are small non-coding RNAs that repress the translation and reduce the stability of target mRNAs in animal cells. Post-transcriptional regulation mediated by miRNAs is a highly conserved mechanism utilized by organisms throughout phylogeny to fine tune gene expression. We document the approaches used to study the function of a single miRNA and miRNA regulation of biological pathways in the sea urchin embryo. The protocols that are described include selection of miRNA inhibitors, test of miRNA direct targets, and the use of target protector morpholinos to evaluate the impact of miRNA inhibition on its targets. Using the described techniques and strategies, the sea urchin researcher will be able to validate a miRNA's direct targets and evaluate how inhibition of the miRNA affects developmental processes. These results will contribute to our understanding of the regulatory roles of miRNAs in development.

Inhibition of microRNA suppression of Dishevelled results in Wnt pathway-associated developmental defects in sea urchin

MicroRNAs (miRNAs) are highly conserved, small non-coding RNAs that regulate gene expressions by binding to the 3' untranslated region of target mRNAs thereby silencing translation. Some miRNAs are key regulators of the Wnt signaling pathways, which impact developmental processes. This study investigates miRNA regulation of different isoforms of Dishevelled (Dvl/Dsh), which encode a key component in the Wnt signaling pathway. The sea urchin Dvl mRNA isoforms have similar spatial distribution in early development, but one isoform is distinctively expressed in the larval ciliary band. We demonstrated that Dvl isoforms are directly suppressed by miRNAs. By blocking miRNA suppression of Dvl isoforms, we observed dose-dependent defects in spicule length, patterning of the primary mesenchyme cells, gut morphology, and cilia. These defects likely result from increased Dvl protein levels, leading to perturbation of Wnt-dependent signaling pathways and additional Dvl-mediated processes. We further demonstrated that overexpression of Dvl isoforms recapitulated some of the Dvl miRNATP-induced phenotypes. Overall, our results indicate that miRNA suppression of Dvl isoforms plays an important role in ensuring proper development and function of primary mesenchyme cells and cilia.

MicroRNA-539 promotes osteoblast proliferation and differentiation and osteoclast apoptosis through the AXNA-dependent Wnt signaling pathway in osteoporotic rats

This study aims to explore the effects of miR-539 on osteoblast proliferation and differentiation and osteoclast apoptosis in a rat model of osteoporosis, and its mechanism involving the regulation of the AXIN1-mediated wingless-Int (Wnt) signaling pathway. A rat model of osteoporosis was successfully established by ovariectomy. With osteoblasts and osteoclasts of rats not receiving ovariectomy in the sham group as control, those of osteoporotic rats were treated with miR-539 inhibitor, miR-539 mimic, and AXIN1 shRNA. The expression of miR-53, AXIN1, the Wnt pathway related-genes, apoptosis related-genes, and osteogenic markers were measured by RT-qPCR and Western blot analysis, respectively. Alkaline phosphatase (ALP) activity in osteoblast and tartrate-resistant acid phosphatase (TRAP) activity in osteoclasts were determined after cell transfection. Osteoblast and osteoclast viability was assayed by CCK-8 assay. Cell cycle and apoptosis of osteoblasts and osteoclasts were detected by flow cytometry. Lastly, alizarin red S staining was used to detect mineralized nodules of osteoblasts. Firstly, we determined that miR-539 was down-regulated in osteoblast and osteoclast of osteoporotic rats and AXIN1 was negatively regulated by miR-539. Additionally, overexpression of miR-539 increased the expressions of β-catenin, LEF1, c-myc, cyclin D1, RUNX2, BGP, BMP-2 in osteoblast as well as β-catenin, RhoA, caspase-3, and Bcl-2 in osteoclasts. Finally, overexpression of miR-539 elevated ALP activity, proliferation, and mineralized nodules in osteoblast and osteoclast apoptosis, with reduced TRAP activity in osteoclasts. Our results demonstrate that miR-539 promotes osteoblast proliferation and differentiation as well as osteoclast apoptosis through the AXIN1-dependent Wnt signaling pathway in osteoporotic rats.

The small GTPase Arf6 regulates sea urchin morphogenesis

The small GTPase Arf6 is a conserved protein that is expressed in all metazoans. Arf6 remodels cytoskeletal actin and mediates membrane protein trafficking between the plasma membrane in its active form and endosomal compartments in its inactive form. While a rich knowledge exists for the cellular functions of Arf6, relatively little is known about its physiological role in development. This study examines the function of Arf6 in mediating cellular morphogenesis in early development. We dissect the function of Arf6 with a loss-of-function morpholino and constitutively active Arf6-Q67L construct. We focus on the two cell types that undergo active directed migration: the primary mesenchyme cells (PMCs) that give rise to the sea urchin skeleton and endodermal cells that form the gut. Our results indicate that Arf6 plays an important role in skeleton formation and PMC migration, in part due to its ability to remodel actin. We also found that embryos injected with Arf6 morpholino have gastrulation defects and embryos injected with constitutively active Arf6 have endodermal cells detached from the gut epithelium with decreased junctional cadherin staining, indicating that Arf6 may mediate the recycling of cadherin. Thus, Arf6 impacts cells that undergo coordinated movement to form embryonic structures in the developing embryo.

microRNA-31 modulates skeletal patterning in the sea urchin embryo

MicroRNAs (miRNAs) are small non-coding RNAs that repress the translation and reduce the stability of target mRNAs in animal cells. microRNA-31 (miR-31) is known to play a role in cancer, bone formation and lymphatic development. However, studies to understand the function of miR-31 in embryogenesis have been limited. We examined the regulatory role of miR-31 in early development using the sea urchin as a model. miR-31 is expressed at all stages of development and its knockdown (KD) disrupts the patterning and function of primary mesenchyme cells (PMCs), which form the embryonic skeleton spicules. We identified that miR-31 directly represses Pmar1, Alx1, Snail and VegfR7 within the PMC gene regulatory network using reporter constructs. Further, blocking the miR-31-mediated repression of Alx1 and/or VegfR7 in the developing embryo resulted in defects in PMC patterning and skeletogenesis. The majority of the mislocalized PMCs in miR-31 KD embryos did not express VegfR10, indicating that miR-31 regulates VegfR gene expression within PMCs. In addition, miR-31 indirectly suppresses Vegf3 expression in the ectoderm. These results indicate that miR-31 coordinately suppresses genes within the PMCs and in the ectoderm to impact PMC patterning and skeletogenesis. This study identifies the novel function and molecular mechanism of miR-31-mediated regulation in the developing embryo.

microRNA regulation of Wnt signaling pathways in development and disease

Wnt signaling pathways and microRNAs (miRNAs) are critical regulators of development. Aberrant Wnt signaling pathways and miRNA levels lead to developmental defects and diverse human pathologies including but not limited to cancer. Wnt signaling pathways regulate a plethora of cellular processes during embryonic development and maintain homeostasis of adult tissues. A majority of Wnt signaling components are regulated by miRNAs which are small noncoding RNAs that are expressed in both animals and plants. In animal cells, miRNAs fine tune gene expression by pairing primarily to the 3'untranslated region of protein coding mRNAs to repress target mRNA translation and/or induce target degradation. miRNA-mediated regulation of signaling transduction pathways is important in modulating dose-sensitive response of cells to signaling molecules. This review discusses components of the Wnt signaling pathways that are regulated by miRNAs in the context of development and diseases. A fundamental understanding of miRNA functions in Wnt signaling transduction pathways may yield new insight into crosstalks of regulatory mechanisms essential for development and disease pathophysiology leading to novel therapeutics.