ZEB1 Represses Neural Differentiation and Cooperates with CTBP2 to Dynamically Regulate Cell Migration during Neocortex Development

Involvement of extracellular vesicle microRNA clusters in developing healthy and Rett syndrome brain organoids

Rett syndrome (RTT) is a neurodevelopmental disorder caused by de novo mutations in the MECP2 gene. Although miRNAs in extracellular vesicles (EVs) have been suggested to play an essential role in several neurological conditions, no prior study has utilized brain organoids to profile EV-derived miRNAs during normal and RTT-affected neuronal development. Here we report the spatiotemporal expression pattern of EV-derived miRNAs in region-specific forebrain organoids generated from female hiPSCs with a MeCP2:R255X mutation and the corresponding isogenic control. EV miRNA and protein expression profiles were characterized at day 0, day 13, day 40, and day 75. Several members of the hsa-miR-302/367 cluster were identified as having a time-dependent expression profile with RTT-specific alterations at the latest developmental stage. Moreover, the miRNA species of the chromosome 14 miRNA cluster (C14MC) exhibited strong upregulation in RTT forebrain organoids irrespective of their spatiotemporal location. Together, our results suggest essential roles of the C14MC and hsa-miR-302/367 clusters in EVs during normal and RTT-associated neurodevelopment, displaying promising prospects as biomarkers for monitoring RTT progression.

Neural Stem Cell Relay from B1 to B2 cells in the adult mouse Ventricular-Subventricular Zone

Neurogenesis and gliogenesis continue in the Ventricular-Subventricular Zone (V-SVZ) of the adult rodent brain. B1 cells are astroglial cells derived from radial glia that function as primary progenitors or neural stem cells (NSCs) in the V-SVZ. B1 cells, which have a small apical contact with the ventricle, decline in numbers during early postnatal life, yet neurogenesis continues into adulthood. Here we found that a second population of V-SVZ astroglial cells (B2 cells), that do not contact the ventricle, function as NSCs in the adult brain. B2 cell numbers increase postnatally, remain constant in 12-month-old mice and decrease by 18 months. Transcriptomic analysis of ventricular-contacting and non-contacting B cells revealed key molecular differences to distinguish B1 from B2 cells. Transplantation and lineage tracing of B2 cells demonstrate their function as primary progenitors for adult neurogenesis. This study reveals how NSC function is relayed from B1 to B2 progenitors to maintain adult neurogenesis.

Zeb1 maintains long-term adult hematopoietic stem cell function and extramedullary hematopoiesis

Emerging evidence implicates the epithelial-mesenchymal transition transcription factor Zeb1 as a critical regulator of hematopoietic stem cell (HSC) differentiation. Whether Zeb1 regulates long-term maintenance of HSC function remains an open question. Using an inducible Mx-1-Cre mouse model that deletes conditional Zeb1 alleles in the adult hematopoietic system, we found that mice engineered to be deficient in Zeb1 for 32 weeks displayed expanded immunophenotypically defined adult HSCs and multipotent progenitors associated with increased abundance of lineage-biased/balanced HSC subsets and augmented cell survival characteristics. During hematopoietic differentiation, persistent Zeb1 loss increased B cells in the bone marrow and spleen and decreased monocyte generation in the peripheral blood. In competitive transplantation experiments, we found that HSCs from adult mice with long-term Zeb1 deletion displayed a cell autonomous defect in multilineage differentiation capacity. Long-term Zeb1 loss perturbed extramedullary hematopoiesis characterized by increased splenic weight and a paradoxical reduction in splenic cellularity that was accompanied by HSC exhaustion, lineage-specific defects, and an accumulation of aberrant, preleukemic like c-kit+CD16/32+ progenitors. Loss of Zeb1 for up to 42 weeks can lead to progressive splenomegaly and an accumulation of Gr-1+Mac-1+ cells, further supporting the notion that long-term expression of Zeb1 suppresses preleukemic activity. Thus, sustained Zeb1 deletion disrupts HSC functionality in vivo and impairs regulation of extramedullary hematopoiesis with potential implications for tumor suppressor functions of Zeb1 in myeloid neoplasms.

Exploring Zika Virus Impact on Endothelial Permeability: Insights into Transcytosis Mechanisms and Vascular Leakage

Treating brain disease is challenging, and the Zika virus (ZIKV) presents a unique obstacle due to its neuroinvasive nature. In this review, we discuss the immunopathogenesis of ZIKV and explore how the virus interacts with the body's immune responses and the role of the protein Mfsd2a in maintaining the integrity of the blood-brain barrier (BBB) during ZIKV neuroinvasion. ZIKV has emerged as a significant public health concern due to its association with severe neurological problems, including microcephaly and Gillain-Barré Syndrome (GBS). Understanding its journey through the brain-particularly its interaction with the placenta and BBB-is crucial. The placenta, which is designed to protect the fetus, becomes a pathway for ZIKV when infected. The BBB is composed of brain endothelial cells, acts as a second barrier, and protects the fetal brain. However, ZIKV finds ways to disrupt these barriers, leading to potential damage. This study explores the mechanisms by which ZIKV enters the CNS and highlights the role of transcytosis, which allows the virus to move through the cells without significantly disrupting the BBB. Although the exact mechanisms of transcytosis are unclear, research suggests that ZIKV may utilize this pathway.

Tissue-specific atlas of trans-models for gene regulation elucidates complex regulation patterns

BACKGROUND

Deciphering gene regulation is essential for understanding the underlying mechanisms of healthy and disease states. While the regulatory networks formed by transcription factors (TFs) and their target genes has been mostly studied with relation to cis effects such as in TF binding sites, we focused on trans effects of TFs on the expression of their transcribed genes and their potential mechanisms.

RESULTS

We provide a comprehensive tissue-specific atlas, spanning 49 tissues of TF variations affecting gene expression through computational models considering two potential mechanisms, including combinatorial regulation by the expression of the TFs, and by genetic variants within the TF. We demonstrate that similarity between tissues based on our discovered genes corresponds to other types of tissue similarity. The genes affected by complex TF regulation, and their modelled TFs, were highly enriched for pharmacogenomic functions, while the TFs themselves were also enriched in several cancer and metabolic pathways. Additionally, genes that appear in multiple clusters are enriched for regulation of immune system while tissue clusters include cluster-specific genes that are enriched for biological functions and diseases previously associated with the tissues forming the cluster. Finally, our atlas exposes multilevel regulation across multiple tissues, where TFs regulate other TFs through the two tested mechanisms.

CONCLUSIONS

Our tissue-specific atlas provides hierarchical tissue-specific trans genetic regulations that can be further studied for association with human phenotypes.

Altered neuroepithelial morphogenesis and migration defects in iPSC-derived cerebral organoids and 2D neural stem cells in familial bipolar disorder

Bipolar disorder (BD) is a severe mental illness that can result from neurodevelopmental aberrations, particularly in familial BD, which may include causative genetic variants. In the present study, we derived cortical organoids from BD patients and healthy (control) individuals from a clinically dense family in the Indian population. Our data reveal that the patient organoids show neurodevelopmental anomalies, including organisational, proliferation and migration defects. The BD organoids show a reduction in both the number of neuroepithelial buds/cortical rosettes and the ventricular zone size. Additionally, patient organoids show a lower number of SOX2-positive and EdU-positive cycling progenitors, suggesting a progenitor proliferation defect. Further, the patient neurons show abnormal positioning in the ventricular/intermediate zone of the neuroepithelial bud. Transcriptomic analysis of control and patient organoids supports our cellular topology data and reveals dysregulation of genes crucial for progenitor proliferation and neuronal migration. Lastly, time-lapse imaging of neural stem cells in 2D in vitro cultures reveals abnormal cellular migration in BD samples. Overall, our study pinpoints a cellular and molecular deficit in BD patient-derived organoids and neural stem cell cultures.

Long non-coding RNA H19 regulates neurogenesis of induced neural stem cells in a mouse model of closed head injury

Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury. We previously reported that induced neural stem cells exert beneficial effects on neural regeneration via cell replacement. However, the neural regeneration efficiency of induced neural stem cells remains limited. In this study, we explored differentially expressed genes and long non-coding RNAs to clarify the mechanism underlying the neurogenesis of induced neural stem cells. We found that H19 was the most downregulated neurogenesis-associated lncRNA in induced neural stem cells compared with induced pluripotent stem cells. Additionally, we demonstrated that H19 levels in induced neural stem cells were markedly lower than those in induced pluripotent stem cells and were substantially higher than those in induced neural stem cell-derived neurons. We predicted the target genes of H19 and discovered that H19 directly interacts with miR-325-3p, which directly interacts with Ctbp2 in induced pluripotent stem cells and induced neural stem cells. Silencing H19 or Ctbp2 impaired induced neural stem cell proliferation, and miR-325-3p suppression restored the effect of H19 inhibition but not the effect of Ctbp2 inhibition. Furthermore, H19 silencing substantially promoted the neural differentiation of induced neural stem cells and did not induce apoptosis of induced neural stem cells. Notably, silencing H19 in induced neural stem cell grafts markedly accelerated the neurological recovery of closed head injury mice. Our results reveal that H19 regulates the neurogenesis of induced neural stem cells. H19 inhibition may promote the neural differentiation of induced neural stem cells, which is closely associated with neurological recovery following closed head injury.

Mowat-Wilson Syndrome: Case Report and Review of ZEB2 Gene Variant Types, Protein Defects and Molecular Interactions

Mowat-Wilson syndrome (MWS) is a rare genetic neurodevelopmental congenital disorder associated with various defects of the zinc finger E-box binding homeobox 2 (ZEB2) gene. The ZEB2 gene is autosomal dominant and encodes six protein domains including the SMAD-binding protein, which functions as a transcriptional corepressor involved in the conversion of neuroepithelial cells in early brain development and as a mediator of trophoblast differentiation. This review summarizes reported ZEB2 gene variants, their types, and frequencies among the 10 exons of ZEB2. Additionally, we summarized their corresponding encoded protein defects including the most common variant, c.2083 C>T in exon 8, which directly impacts the homeodomain (HD) protein domain. This single defect was found in 11% of the 298 reported patients with MWS. This review demonstrates that exon 8 encodes at least three of the six protein domains and accounts for 66% (198/298) of the variants identified. More than 90% of the defects were due to nonsense or frameshift changes. We show examples of protein modeling changes that occurred as a result of ZEB2 gene defects. We also report a novel pathogenic variant in exon 8 in a 5-year-old female proband with MWS. This review further explores other genes predicted to be interacting with the ZEB2 gene and their predicted gene-gene molecular interactions with protein binding effects on embryonic multi-system development such as craniofacial, spine, brain, kidney, cardiovascular, and hematopoiesis.

Loss-of-function variants in ZEB1 cause dominant anomalies of the corpus callosum with favourable cognitive prognosis

BACKGROUND

The neurodevelopmental prognosis of anomalies of the corpus callosum (ACC), one of the most frequent brain malformations, varies extremely, ranging from normal development to profound intellectual disability (ID). Numerous genes are known to cause syndromic ACC with ID, whereas the genetics of ACC without ID remains poorly deciphered.

METHODS

Through a collaborative work, we describe here ZEB1, a gene previously involved in an ophthalmological condition called type 3 posterior polymorphous corneal dystrophy, as a new dominant gene of ACC. We report a series of nine individuals with ACC (including three fetuses terminated due to ACC) carrying a ZEB1 heterozygous loss-of-function (LoF) variant, identified by exome sequencing.

RESULTS

In five cases, the variant was inherited from a parent with a normal corpus callosum, which illustrates the incomplete penetrance of ACC in individuals with an LoF in ZEB1. All patients reported normal schooling and none of them had ID. Neuropsychological assessment in six patients showed either normal functioning or heterogeneous cognition. Moreover, two patients had a bicornuate uterus, three had a cardiovascular anomaly and four had macrocephaly at birth, which suggests a larger spectrum of malformations related to ZEB1.

CONCLUSION

This study shows ZEB1 LoF variants cause dominantly inherited ACC without ID and extends the extraocular phenotype related to this gene.

The mesodermal and myogenic specification of hESCs depend on ZEB1 and are inhibited by ZEB2

Human embryonic stem cells (hESCs) can differentiate into any cell lineage. Here, we report that ZEB1 and ZEB2 promote and inhibit mesodermal-to-myogenic specification of hESCs, respectively. Knockdown and/or overexpression experiments of ZEB1, ZEB2, or PAX7 in hESCs indicate that ZEB1 is required for hESC Nodal/Activin-mediated mesodermal specification and PAX7+ human myogenic progenitor (hMuP) generation, while ZEB2 inhibits these processes. ZEB1 downregulation induces neural markers, while ZEB2 downregulation induces mesodermal/myogenic markers. Mechanistically, ZEB1 binds to and transcriptionally activates the PAX7 promoter, while ZEB2 binds to and activates the promoter of the neural OTX2 marker. Transplanting ZEB1 or ZEB2 knocked down hMuPs into the muscles of a muscular dystrophy mouse model, showing that hMuP engraftment and generation of dystrophin-positive myofibers depend on ZEB1 and are inhibited by ZEB2. The mouse model results suggest that ZEB1 expression and/or downregulating ZEB2 in hESCs may also enhance hESC regenerative capacity for human muscular dystrophy therapy.

The epithelial-mesenchymal plasticity landscape: principles of design and mechanisms of regulation

Epithelial-mesenchymal plasticity (EMP) enables cells to interconvert between several states across the epithelial-mesenchymal landscape, thereby acquiring hybrid epithelial/mesenchymal phenotypic features. This plasticity is crucial for embryonic development and wound healing, but also underlies the acquisition of several malignant traits during cancer progression. Recent research using systems biology and single-cell profiling methods has provided novel insights into the main forces that shape EMP, which include the microenvironment, lineage specification and cell identity, and the genome. Additionally, key roles have emerged for hysteresis (cell memory) and cellular noise, which can drive stochastic transitions between cell states. Here, we review these forces and the distinct but interwoven layers of regulatory control that stabilize EMP states or facilitate epithelial-mesenchymal transitions (EMTs) and discuss the therapeutic potential of manipulating the EMP landscape.

Proteomic investigation of neural stem cell to oligodendrocyte precursor cell differentiation reveals phosphorylation-dependent Dclk1 processing

Oligodendrocytes are generated via a two-step mechanism from pluripotent neural stem cells (NSCs): after differentiation of NSCs to oligodendrocyte precursor/NG2 cells (OPCs), they further develop into mature oligodendrocytes. The first step of this differentiation process is only incompletely understood. In this study, we utilized the neurosphere assay to investigate NSC to OPC differentiation in a time course-dependent manner by mass spectrometry-based (phospho-) proteomics. We identify doublecortin-like kinase 1 (Dclk1) as one of the most prominently regulated proteins in both datasets, and show that it undergoes a gradual transition between its short/long isoform during NSC to OPC differentiation. This is regulated by phosphorylation of its SP-rich region, resulting in inhibition of proteolytic Dclk1 long cleavage, and therefore Dclk1 short generation. Through interactome analyses of different Dclk1 isoforms by proximity biotinylation, we characterize their individual putative interaction partners and substrates. All data are available via ProteomeXchange with identifier PXD040652.

CtBP Neuroprotective Role in Toxin-Based Parkinson's Disease Models: From Expression Pattern to Dopaminergic Survival

C-terminal binding proteins (CtBP) are transcriptional co-repressors regulating gene expression. CtBP promote neuronal survival through repression of pro-apoptotic genes, and may represent relevant targets for neurodegenerative disorders, such as Parkinson's disease (PD). Nevertheless, evidence of the role of CtBP1 and CtBP2 in neurodegeneration are scarce. Herein, we showed that CtBP1 and CtBP2 are expressed in neurons, dopaminergic neurons, astrocytes, and microglia in the substantia nigra (SN) and striatum of adult mice. Old mice showed a lower expression of CtBP1 in the SN and higher expression of CtPB2 in the SN and striatum compared with adult mice. In vivo models for PD (paraquat, MPTP, 6-OHDA) showed increased expression of CtBP1 in the SN and striatum while CtBP2 expression was increased in the striatum of paraquat-treated rats only. Moreover, an increased expression of both CtBP was found in a dopaminergic cell line (N27) exposed to 6-OHDA. In the 6-OHDA PD model, we found a dual effect using an unspecific ligand of CtBP, the 4-methylthio 2-oxobutyric acid (MTOB): higher concentrations (e.g. 2500 µM, 1000 µM) inhibited dopaminergic survival, while at 250 μM it counteracted cell death. In vitro, this latter protective role was absent after the siRNA silencing of CtBP1 or CtBP2. Altogether, this is the first report exploring the cellular and regional expression pattern of CtBP in the nigrostriatal pathway and the neuroprotective role in PD toxin-based models. CtBP could counteract dopaminergic cell death in the 6-OHDA PD model and, therefore, CtBP function and therapeutic potential in PD should be further explored.

Transcriptional control of embryonic and adult neural progenitor activity

Neural precursors generate neurons in the embryonic brain and in restricted niches of the adult brain in a process called neurogenesis. The precise control of cell proliferation and differentiation in time and space required for neurogenesis depends on sophisticated orchestration of gene transcription in neural precursor cells. Much progress has been made in understanding the transcriptional regulation of neurogenesis, which relies on dose- and context-dependent expression of specific transcription factors that regulate the maintenance and proliferation of neural progenitors, followed by their differentiation into lineage-specified cells. Here, we review some of the most widely studied neurogenic transcription factors in the embryonic cortex and neurogenic niches in the adult brain. We compare functions of these transcription factors in embryonic and adult neurogenesis, highlighting biochemical, developmental, and cell biological properties. Our goal is to present an overview of transcriptional regulation underlying neurogenesis in the developing cerebral cortex and in the adult brain.

ZEB1 is a Subgroup-Specific Marker of Prognosis and Potential Drug Target in Medulloblastoma

Medulloblastoma (MB) is a malignant brain tumor that afflicts mostly children and adolescents and presents four distinct molecular subgroups, known as WNT, SHH, Group 3, and Group 4. ZEB1 is a transcription factor that promotes the expression of mesenchymal markers while restraining expression of epithelial and polarity genes. Because of ZEB1 involvement in cerebellum development, here we investigated the role of ZEB1 in MB. We found increased expression of ZEB1 in MB tumor samples compared to normal cerebellar tissue. Expression was higher in the SHH subgroup when compared to all other MB molecular subgroups. High ZEB1 expression was associated with poor prognosis in Group 3 and Group 4, whereas in patients with WNT tumors poorer prognosis were related to lower ZEB1 expression. There was a moderate correlation between ZEB1 and MYC expression in Group 3 and Group 4 MB. Treatment with the immunomodulator and histone deacetylase (HDAC) inhibitor fingolimod (FTY720) reduced ZEB1 expression specifically in D283 cells, which are representative of Group 3 and Group 4 MB. These findings reveal novel subgroup-specific associations of ZEB1 expression with survival in patients with MB and suggest that ZEB1 expression can be reduced by pharmacological agents that target HDAC activity.

Exosomal ZEB1 Derived from Neural Stem Cells Reduces Inflammation Injury in OGD/R-Treated Microglia via the GPR30-TLR4-NF-κB Axis

Ischemic stroke (IS) is the most common type of stroke and the second leading cause of death overall. Neural stem cells play protective roles in IS, but the underlying mechanism remains to be determined. Neural stem cells (NSC) were obtained from the fetal brain tissue of C57BL/6J mice. NSC-derived exosomes (NSC-Exos) were identified in the conditioned medium. Internalization of NSC-Exos was analyzed by fluorescence microscopy. In vitro microglia ischemic stroke injury model was induced using oxygen glucose deprivation/re-oxygenation (OGD/R) method. Cell viability and inflammation were analyzed by MTT, qPCR, ELISA and Western blotting assay. Interaction between ZEB1 and the promoter of GPR30 was verified by luciferase assay and chromatin immunoprecipitation. NSC-Exos prevented OGD/R-mediated inhibition of cell survival and the production of inflammatory cytokines in microglia cells. NSC-Exos increased ZEB1 expression in OGD/R-treated microglia. Down-regulation of ZEB1 expression in NSC-Exos abolished NSC-Exos' protective effects on OGD/R-treated microglia. ZEB1 bound to the promoter region of GPR30 and promoted its expression. Inhibiting GPR30 reversed NSC-Exos effects on cell viability and inflammation injury in OGD/R-treated microglia. Our study demonstrated that NSC exerted cytoprotective roles through release of exosomal ZEB1,which transcriptionally upregulated GPR30 expression, resulting in a reduction in TLR4/NF-κB pathway-induced inflammation. These findings shed light on NSC-Exos' cytoprotective mechanism and highlighted its potential application in the treatment of IS.

Deciphering transcription factors and their corresponding regulatory elements during inhibitory interneuron differentiation using deep neural networks

During neurogenesis, the generation and differentiation of neuronal progenitors into inhibitory gamma-aminobutyric acid-containing interneurons is dependent on the combinatorial activity of transcription factors (TFs) and their corresponding regulatory elements (REs). However, the roles of neuronal TFs and their target REs in inhibitory interneuron progenitors are not fully elucidated. Here, we developed a deep-learning-based framework to identify enriched TF motifs in gene REs (eMotif-RE), such as poised/repressed enhancers and putative silencers. Using epigenetic datasets (e.g., ATAC-seq and H3K27ac/me3 ChIP-seq) from cultured interneuron-like progenitors, we distinguished between active enhancer sequences (open chromatin with H3K27ac) and non-active enhancer sequences (open chromatin without H3K27ac). Using our eMotif-RE framework, we discovered enriched motifs of TFs such as ASCL1, SOX4, and SOX11 in the active enhancer set suggesting a cooperativity function for ASCL1 and SOX4/11 in active enhancers of neuronal progenitors. In addition, we found enriched ZEB1 and CTCF motifs in the non-active set. Using an in vivo enhancer assay, we showed that most of the tested putative REs from the non-active enhancer set have no enhancer activity. Two of the eight REs (25%) showed function as poised enhancers in the neuronal system. Moreover, mutated REs for ZEB1 and CTCF motifs increased their in vivo activity as enhancers indicating a repressive effect of ZEB1 and CTCF on these REs that likely function as repressed enhancers or silencers. Overall, our work integrates a novel framework based on deep learning together with a functional assay that elucidated novel functions of TFs and their corresponding REs. Our approach can be applied to better understand gene regulation not only in inhibitory interneuron differentiation but in other tissue and cell types.

Whole exome sequencing in dense families suggests genetic pleiotropy amongst Mendelian and complex neuropsychiatric syndromes

Whole Exome Sequencing (WES) studies provide important insights into the genetic architecture of serious mental illness (SMI). Genes that are central to the shared biology of SMIs may be identified by WES in families with multiple affected individuals with diverse SMI (F-SMI). We performed WES in 220 individuals from 75 F-SMI families and 60 unrelated controls. Within pedigree prioritization employed criteria of rarity, functional consequence, and sharing by ≥ 3 affected members. Across the sample, gene and gene-set-wide case-control association analysis was performed with Sequence Kernel Association Test (SKAT). In 14/16 families with ≥ 3 sequenced affected individuals, we identified a total of 78 rare predicted deleterious variants in 78 unique genes shared by ≥ 3 members with SMI. Twenty (25%) genes were implicated in monogenic CNS syndromes in OMIM (OMIM-CNS), a fraction that is a significant overrepresentation (Fisher's Exact test OR = 2.47, p = 0.001). In gene-set SKAT, statistically significant association was noted for OMIM-CNS gene-set (SKAT-p = 0.005) but not the synaptic gene-set (SKAT-p = 0.17). In this WES study in F-SMI, we identify private, rare, protein altering variants in genes previously implicated in Mendelian neuropsychiatric syndromes; suggesting pleiotropic influences in neurodevelopment between complex and Mendelian syndromes.

Post-Translational Modification of ZEB Family Members in Cancer Progression

Post-translational modification (PTM), the essential regulatory mechanisms of proteins, play essential roles in physiological and pathological processes. In addition, PTM functions in tumour development and progression. Zinc finger E-box binding homeobox (ZEB) family homeodomain transcription factors, such as ZEB1 and ZEB2, play a pivotal role in tumour progression and metastasis by induction epithelial-mesenchymal transition (EMT), with activation of stem cell traits, immune evasion and epigenetic reprogramming. However, the relationship between ZEB family members' post-translational modification (PTM) and tumourigenesis remains largely unknown. Therefore, we focussed on the PTM of ZEBs and potential therapeutic approaches in cancer progression. This review provides an overview of the diverse functions of ZEBs in cancer and the mechanisms and therapeutic implications that target ZEB family members' PTMs.

The role of the ZEB1–neuroinflammation axis in CNS disorders

Zinc finger E-box binding homeobox 1 (ZEB1) is a master modulator of the epithelial–mesenchymal transition (EMT), a process whereby epithelial cells undergo a series of molecular changes and express certain characteristics of mesenchymal cells. ZEB1, in association with other EMT transcription factors, promotes neuroinflammation through changes in the production of inflammatory mediators, the morphology and function of immune cells, and multiple signaling pathways that mediate the inflammatory response. The ZEB1–neuroinflammation axis plays a pivotal role in the pathogenesis of different CNS disorders, such as brain tumors, multiple sclerosis, cerebrovascular diseases, and neuropathic pain, by promoting tumor cell proliferation and invasiveness, formation of the hostile inflammatory micromilieu surrounding neuronal tissues, dysfunction of microglia and astrocytes, impairment of angiogenesis, and dysfunction of the blood–brain barrier. Future studies are needed to elucidate whether the ZEB1–neuroinflammation axis could serve as a diagnostic, prognostic, and/or therapeutic target for CNS disorders.

A multi-omics approach to visualize early neuronal differentiation from hESCs in 4D

Neuronal differentiation of pluripotent stem cells is an established method to study physiology, disease, and medication safety. However, the sequence of events in human neuronal differentiation and the ability of in vitro models to recapitulate early brain development are poorly understood. We developed a protocol optimized for the study of early human brain development and neuropharmacological applications. We comprehensively characterized gene expression and epigenetic profiles at four timepoints, because the cells differentiate from embryonic stem cells towards a heterogeneous population of progenitors, immature and mature neurons bearing telencephalic signatures. A multi-omics roadmap of neuronal differentiation, combined with searchable interactive gene analysis tools, allows for extensive exploration of early neuronal development and the effect of medications.

Matrix stiffness exacerbates the proinflammatory responses of vascular smooth muscle cell through the DDR1-DNMT1 mechanotransduction axis

Vascular smooth muscle cell (vSMC) is highly plastic as its phenotype can change in response to mechanical cues inherent to the extracellular matrix (ECM). VSMC may be activated from its quiescent contractile phenotype to a proinflammatory phenotype, whereby the cell secretes chemotactic and inflammatory cytokines, e.g. MCP1 and IL6, to functionally regulate monocyte and macrophage infiltration during the development of various vascular diseases including arteriosclerosis. Here, by culturing vSMCs on polyacrylamide (PA) substrates with variable elastic moduli, we discovered a role of discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase that binds collagens, in mediating the mechanical regulation of vSMC gene expression, phenotype, and proinflammatory responses. We found that ECM stiffness induced DDR1 phosphorylation, oligomerization, and endocytosis to repress the expression of DNA methyltransferase 1 (DNMT1), very likely in a collagen-independent manner. The DDR1-to-DNMT1 signaling was sequentially mediated by the extracellular signal-regulated kinases (ERKs) and p53 pathways. ECM stiffness primed vSMC to a proinflammatory phenotype and this regulation was diminished by DDR1 inhibition. In agreement with the in vitro findings, increased DDR1 phosphorylation was observed in human arterial stiffening. DDR1 inhibition in mouse attenuated the acute injury or adenine diet-induced vascular stiffening and inflammation. Furthermore, mouse vasculature with SMC-specific deletion of Dnmt1 exhibited proinflammatory and stiffening phenotypes. Our study demonstrates a role of SMC DDR1 in perceiving the mechanical microenvironments and down-regulating expression of DNMT1 to result in vascular pathologies and has potential implications for optimization of engineering artificial vascular grafts and vascular networks.

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DDR1 is a mechanosensor in vSMC to perceive ECM stiffness in a collagen binding-independent way.

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Activation of DDR1 leads to repression of DNMT1 expression via the ERK-p53 pathway.

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The DDR1-DNMT1 axis mediates ECM stiffening-induced vascular inflammation.

The dorsal hippocampal CA3 regulates spatial reference memory through the CtBP2/GluR2 pathway

The dorsal hippocampus plays a pivotal role in spatial memory. However, the role of subregion-specific molecular pathways in spatial cognition remains unclear. We observed that the transcriptional coregulator C-terminal binding protein 2 (CtBP2) presented CA3-specific enrichment in expression. RNAi interference of CtBP2 in the dorsal CA3 (dCA3) neurons, but not the ventral CA3 (vCA3), specifically impaired spatial reference memory and reduced the expression of GluR2, the calcium permeability determinant subunit of AMPA receptors. Application of an antagonist for GluR2-absent calcium permeable AMPA receptors rescued spatial memory deficits in dCA3 CtBP2 knockdown animals. Transcriptomic analysis suggest that CtBP2 may regulate GluR2 protein level through post-translational mechanisms, especially by the endocytosis pathway which regulates AMPA receptor sorting. Consistently, CtBP2 deficiency altered the mRNA expression of multiple endocytosis-regulatory genes, and CtBP2 knockdown in primary hippocampal neurons enhanced GluR2-containing AMPA receptor endocytosis. Together, our results provide evidence that the dCA3 regulates spatial reference memory by the CtBP2/GluR2 pathway through the modulation of calcium permeable AMPA receptors.

Molecular cytogenetic analysis of partial monosomy 10p and trisomy 10q resulting from familial pericentric inversion (10): a first case report in Chinese population

Background

Chromosome aberrations of 10p monosomy and 10q trisomy resulting from parental pericentric inversion 10 are extremely rare, and to date, very few reports have been published on the matter.

Case Presentation

A 30-year-old pregnant woman with recurrent pregnancy loss is enrolled in this research. In this pregnancy, spontaneous abortion occurred in the first trimester of her pregnancy. Chromosomal microarray analysis of the abortion tissue showed a partial 10p monosomy (arr[GRCh37] 10p15.3p11.21(100,047_34,848,853) × 1) and a duplication of 10q (arr[GRCh37] 10q26.13q26.3(126,093,990_135,426,386) × 3). Further parental karyotype analysis indicated that the chromosomal abnormalities in the fetus was resulted from paternal pericenric inversion inv(10)(p11.21q26.13). This study presents the first case of a large deletion of 10p combined with 10q trisomy, resulting in pregnancy loss. Of these two manifestations, the large deletion of chromosome 10p may be the primary reason for spontaneous abortion in this subject.

Conclusions

This study presents the first case of partial 10p monosomy associated with 10q trisomy in Chinese population. It provides more information on the chromosome aberration of 10p monosomy and 10q trisomy and further strengthens the application value of microarray in the molecular etiological diagnosis of recurrent spontaneous abortion.

Neuronal Polarity Pathways as Central Integrators of Cell-Extrinsic Information During Interactions of Neural Progenitors With Germinal Niches

Germinal niche interactions and their effect on developing neurons have become the subject of intense investigation. Dissecting the complex interplay of cell-extrinsic and cell-intrinsic factors at the heart of these interactions reveals the critical basic mechanisms of neural development and how it goes awry in pediatric neurologic disorders. A full accounting of how developing neurons navigate their niches to mature and integrate into a developing neural circuit requires a combination of genetic characterization of and physical access to neurons and their supporting cell types plus transformative imaging to determine the cell biological and gene-regulatory responses to niche cues. The mouse cerebellar cortex is a prototypical experimental system meeting all of these criteria. The lessons learned therein have been scaled to other model systems and brain regions to stimulate discoveries of how developing neurons make many developmental decisions. This review focuses on how mouse cerebellar granule neuron progenitors interact with signals in their germinal niche and how that affects the neuronal differentiation and cell polarization programs that underpin lamination of the developing cerebellum. We show how modeling of these mechanisms in other systems has added to the growing evidence of how defective neuronal polarity contributes to developmental disease.

Zika Virus Neuropathogenesis: The Different Brain Cells, Host Factors and Mechanisms Involved

Zika virus (ZIKV), despite being discovered six decades earlier, became a major health concern only after an epidemic in French Polynesia and an increase in the number of microcephaly cases in Brazil. Substantial evidence has been found to support the link between ZIKV and neurological complications in infants. The virus targets various cells in the brain, including radial glial cells, neural progenitor cells (NPCs), astrocytes, microglial and glioblastoma stem cells. It affects the brain cells by exploiting different mechanisms, mainly through apoptosis and cell cycle dysregulation. The modulation of host immune response and the inflammatory process has also been demonstrated to play a critical role in ZIKV induced neurological complications. In addition to that, different ZIKV strains have exhibited specific neurotropism and unique molecular mechanisms. This review provides a comprehensive and up-to-date overview of ZIKV-induced neuroimmunopathogenesis by dissecting its main target cells in the brain, and the underlying cellular and molecular mechanisms. We highlighted the roles of the different ZIKV host factors and how they exploit specific host factors through various mechanisms. Overall, it covers key components for understanding the crosstalk between ZIKV and the brain.

Loss of neurodevelopmental-associated miR-592 impairs neurogenesis and causes social interaction deficits

microRNA-592 (miR-592) has been linked to neurogenesis, but the influence of miR-592 knockout in vivo remains unknown. Here, we report that miR-592 knockout represses IPC-to-mature neuron transition, impairs motor coordination and reduces social interaction. Combining the RNA-seq and tandem mass tagging-based quantitative proteomics analysis (TMT protein quantification) and luciferase reporter assays, we identified MeCP2 as the direct targetgene of miR-592 in the mouse cortex. In Tg(MECP2) mice, lipofection of miR-592 efficiently reduced MECP2 expression in the brains of Tg(MECP2) mice at E14.5. Furthermore, treatment with miR-592 partially ameliorated the autism-like phenotypes observed in adult Tg(MECP2) mice. The findings demonstrate that miR-592 might play a novel role in treating the neurodevelopmental-associated disorder.

CtBP2 interacts with TGIF to promote the progression of esophageal squamous cell cancer through the Wnt/β‑catenin pathway

C-terminal-binding protein 2 (CtBP2), a transcriptional co-repressor, plays a main role in tumorigenesis and in the development of multiple tumors. Transforming growth interacting factor (TGIF) is involved in a number of cellular signal transduction pathways and is related to tumor occurrence and development. In the present study, the proteins interacting with CtBP2 were identified and the mechanisms underlying the biological activity of CtBP2 in esophageal squamous cell carcinoma (ESCC) were investigated. The Search Tool for the Retrieval of Interacting Genes (STRING) database was used to search for known proteins interacting with CtBP2, and co-immunoprecipitation (Co-IP) assay was performed to validate the interactions. Reverse transcription-quantitative PCR (RT-qPCR), immunohistochemistry (IHC) and western blot analysis were performed to examine the expression levels of CtBP2 and TGIF in ESCC. The correlation between CtBP2 and TGIF was analyzed using Gene Expression Profiling Interactive Analysis (GEPIA) by Pearson's correlation analysis, and the co-localization of CtBP2 with TGIF in the ECA109 cells was identified using immunofluorescence staining. XAV939 treatment, CCK-8, 5-ethynyl-2′-deoxyuridine (EdU) staining, wound healing and Transwell assays were performed to investigate the signaling pathways involved in the biological activity of CtBP2 in ECA109 cells. According to the results obtained from STRING and Co-IP analysis, an interaction between CtBP2 and TGIF was indicated, and these proteins were co-localized in the nucleus. CtBP2 and TGIF mRNA and protein expression levels were robustly and simultaneously increased in both ESCC tissues and cell lines. There was a direct correlation between CtBP2 and TGIF expression levels in ESCC tissues, and both were significantly associated with metastasis and survival. The TGIF and CtBP2 expression levels were significantly increased or decreased simultaneously, in ECA109 cells transfected with LV-CtBP2 or sh-CtBP2, and vice versa. According to the results of CCK-8 assay, EdU staining and Transwell assay, CtBP2 promoted the proliferation, migration and invasion of ECA109 cells through the Wnt/β-catenin pathway. On the whole, the present study demonstrates that CtBP2 interacts with TGIF and promotes the malignant progression of ESCC through the Wnt/β-catenin pathway.

PCAT6 May Be a Whistler and Checkpoint Target for Precision Therapy in Human Cancers

Simple Summary

Prostate cancer-associated transcript 6 (PCAT6), as a newly discovered carcinogenic long non-coding RNA (lncRNA), is abnormally expressed in multiple diseases. With the accumulation of studies on PCAT6, we have a deeper understanding of its biological functions and mechanisms. Therefore, in this review, the various molecular mechanisms by which PCAT6 promotes multiple tumorigenesis and progression are summarized and discussed. Furthermore, its potential diagnostic, prognostic, and immunotherapeutic values are also clarified.

Abstract

LncRNAs are involved in the occurrence and progressions of multiple cancers. Emerging evidence has shown that PCAT6, a newly discovered carcinogenic lncRNA, is abnormally elevated in various human malignant tumors. Until now, PCAT6 has been found to sponge various miRNAs to activate the signaling pathways, which further affects tumor cell proliferation, migration, invasion, cycle, apoptosis, radioresistance, and chemoresistance. Moreover, PCAT6 has been shown to exert biological functions beyond ceRNAs. In this review, we summarize the biological characteristics of PCAT6 in a variety of human malignancies and describe the biological mechanisms by which PCAT6 can facilitate tumor progression. Finally, we discuss its diagnostic and prognostic values and clinical applications in various human malignancies.

Comprehensive multi-omics integration identifies differentially active enhancers during human brain development with clinical relevance

BACKGROUND

Non-coding regulatory elements (NCREs), such as enhancers, play a crucial role in gene regulation, and genetic aberrations in NCREs can lead to human disease, including brain disorders. The human brain is a complex organ that is susceptible to numerous disorders; many of these are caused by genetic changes, but a multitude remain currently unexplained. Understanding NCREs acting during brain development has the potential to shed light on previously unrecognized genetic causes of human brain disease. Despite immense community-wide efforts to understand the role of the non-coding genome and NCREs, annotating functional NCREs remains challenging.

METHODS

Here we performed an integrative computational analysis of virtually all currently available epigenome data sets related to human fetal brain.

RESULTS

Our in-depth analysis unravels 39,709 differentially active enhancers (DAEs) that show dynamic epigenomic rearrangement during early stages of human brain development, indicating likely biological function. Many of these DAEs are linked to clinically relevant genes, and functional validation of selected DAEs in cell models and zebrafish confirms their role in gene regulation. Compared to enhancers without dynamic epigenomic rearrangement, DAEs are subjected to higher sequence constraints in humans, have distinct sequence characteristics and are bound by a distinct transcription factor landscape. DAEs are enriched for GWAS loci for brain-related traits and for genetic variation found in individuals with neurodevelopmental disorders, including autism.

CONCLUSION

This compendium of high-confidence enhancers will assist in deciphering the mechanism behind developmental genetics of human brain and will be relevant to uncover missing heritability in human genetic brain disorders.

Zeb1 modulates hematopoietic stem cell fates required for suppressing acute myeloid leukemia

Zeb1, a zinc finger E-box binding homeobox epithelial-mesenchymal transition (EMT) transcription factor, confers properties of "stemness," such as self-renewal, in cancer. Yet little is known about the function of Zeb1 in adult stem cells. Here, we used the hematopoietic system as a well-established paradigm of stem cell biology to evaluate Zeb1-mediated regulation of adult stem cells. We employed a conditional genetic approach using the Mx1-Cre system to specifically knock out (KO) Zeb1 in adult hematopoietic stem cells (HSCs) and their downstream progeny. Acute genetic deletion of Zeb1 led to rapid-onset thymic atrophy and apoptosis-driven loss of thymocytes and T cells. A profound cell-autonomous self-renewal defect and multilineage differentiation block were observed in Zeb1-KO HSCs. Loss of Zeb1 in HSCs activated transcriptional programs of deregulated HSC maintenance and multilineage differentiation genes and of cell polarity consisting of cytoskeleton-, lipid metabolism/lipid membrane-, and cell adhesion-related genes. Notably, epithelial cell adhesion molecule (EpCAM) expression was prodigiously upregulated in Zeb1-KO HSCs, which correlated with enhanced cell survival, diminished mitochondrial metabolism, ribosome biogenesis, and differentiation capacity and an activated transcriptomic signature associated with acute myeloid leukemia (AML) signaling. ZEB1 expression was downregulated in AML patients, and Zeb1 KO in the malignant counterparts of HSCs - leukemic stem cells (LSCs) - accelerated MLL-AF9- and Meis1a/Hoxa9-driven AML progression, implicating Zeb1 as a tumor suppressor in AML LSCs. Thus, Zeb1 acts as a transcriptional regulator in hematopoiesis, critically coordinating HSC self-renewal, apoptotic, and multilineage differentiation fates required to suppress leukemic potential in AML.

Meta-Analysis of Brain Gene Expression Data from Mouse Model Studies of Maternal Immune Activation Using Poly(I:C)

Maternal immune activation (MIA) is a known risk factor for schizophrenia (SCZ) and autism spectrum disorder (ASD) and is often modelled in animal studies in order to study the effect of prenatal infection on brain function including behaviour and gene expression. Although the effect of MIA on gene expression are highly heterogeneous, combining data from multiple gene expression studies in a robust method may shed light on the true underlying biological effects caused by MIA and this could inform studies of SCZ and ASD. This study combined four RNA-seq and microarray datasets in an overlap analysis and ranked meta-analysis in order to investigate genes, pathways and cell types dysregulated in the MIA mouse models. Genes linked to SCZ and ASD and crucial in neurodevelopmental processes including neural tube folding, regulation of cellular stress and neuronal/glial cell differentiation were among the most consistently dysregulated in these ranked analyses. Gene ontologies including K+ ion channel function, neuron and glial cell differentiation, synaptic structure, axonal outgrowth, cilia function and lipid metabolism were also strongly implicated. Single-cell analysis identified excitatory and inhibitory cell types in the cortex, hippocampus and striatum that may be affected by MIA and are also enriched for genes associated with SCZ, ASD and cognitive phenotypes. This points to the cellular location of molecular mechanisms that may be consistent between the MIA model and neurodevelopmental disease, improving our understanding of its utility to study prenatal infection as an environmental stressor.

The transcription factor ZEB1 regulates stem cell self-renewal and cell fate in the adult hippocampus

Radial glia-like (RGL) stem cells persist in the adult mammalian hippocampus, where they generate new neurons and astrocytes throughout life. The process of adult neurogenesis is well documented, but cell-autonomous factors regulating neuronal and astroglial differentiation are incompletely understood. Here, we evaluate the functions of the transcription factor zinc-finger E-box binding homeobox 1 (ZEB1) in adult hippocampal RGL cells using a conditional-inducible mouse model. We find that ZEB1 is necessary for self-renewal of active RGL cells. Genetic deletion of Zeb1 causes a shift toward symmetric cell division that consumes the RGL cell and generates pro-neuronal progenies, resulting in an increase of newborn neurons and a decrease of newly generated astrocytes. We identify ZEB1 as positive regulator of the ets-domain transcription factor ETV5 that is critical for asymmetric division.

Oncogenic functions of ZEB1 in pediatric solid cancers: interplays with microRNAs and long noncoding RNAs

The transcription factor Zinc finger E-box binding 1 (ZEB1) displays a range of regulatory activities in cell function and embryonic development, including driving epithelial-mesenchymal transition. Several aspects of ZEB1 function can be regulated by its functional interactions with noncoding RNA types, namely microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). Increasing evidence indicates that ZEB1 importantly influences cancer initiation, tumor progression, metastasis, and resistance to treatment. Cancer is the main disease-related cause of death in children and adolescents. Although the role of ZEB1 in pediatric cancer is still poorly understood, emerging findings have shown that it is expressed and regulates childhood solid tumors including osteosarcoma, retinoblastoma, neuroblastoma, and central nervous system tumors. Here, we review the evidence supporting a role for ZEB1, and its interplays with miRNAs and lncRNAs, in pediatric cancers.

The transrepression and transactivation roles of CtBPs in the pathogenesis of different diseases

Gene transcription is strictly controlled by transcriptional complexes, which are assemblies of transcription factors, transcriptional regulators, and co-regulators. Mammalian genomes encode two C-terminal-binding proteins (CtBPs), CtBP1 and CtBP2, which are both well-known transcriptional corepressors of oncogenic processes. Their overexpression in tumors is associated with malignant behavior, such as uncontrolled cell proliferation, migration, and invasion, as well as with an increase in the epithelial-mesenchymal transition. CtBPs coordinate with other transcriptional regulators, such as histone deacetylases (HDACs) and histone acetyltransferases (p300 and CBP [CREBP-binding protein]) that contain the PXDLS motif, and with transcription factors to assemble transcriptional complexes that dock onto the promoters of genes to initiate gene transcription. Emerging evidence suggests that CtBPs function as both corepressors and coactivators in different biological processes ranging from apoptosis to inflammation and osteogenesis. Therapeutic targeting of CtBPs or the interactions required to form transcriptional complexes has also shown promising effects in preventing disease progression. This review summarizes the most recent progress in the study of CtBP functions and therapeutic inhibitors in different biological processes. This knowledge may enable a better understanding of the complexity of the roles of CtBPs, while providing new insights into therapeutic strategies that target CtBPs.

Cell-type-specific effects of genetic variation on chromatin accessibility during human neuronal differentiation

Common genetic risk for neuropsychiatric disorders is enriched in regulatory elements active during cortical neurogenesis. However, it remains poorly understood as to how these variants influence gene regulation. To model the functional impact of common genetic variation on the noncoding genome during human cortical development, we performed the assay for transposase accessible chromatin using sequencing (ATAC-seq) and analyzed chromatin accessibility quantitative trait loci (QTL) in cultured human neural progenitor cells and their differentiated neuronal progeny from 87 donors. We identified significant genetic effects on 988/1,839 neuron/progenitor regulatory elements, with highly cell-type and temporally specific effects. A subset (roughly 30%) of chromatin accessibility-QTL were also associated with changes in gene expression. Motif-disrupting alleles of transcriptional activators generally led to decreases in chromatin accessibility, whereas motif-disrupting alleles of repressors led to increases in chromatin accessibility. By integrating cell-type-specific chromatin accessibility-QTL and brain-relevant genome-wide association data, we were able to fine-map and identify regulatory mechanisms underlying noncoding neuropsychiatric disorder risk loci.

Proteomic Analysis of Zeb1 Interactome in Breast Carcinoma Cells

Breast cancer is the most frequently diagnosed malignant neoplasm and the second leading cause of cancer death among women. Epithelial-to-mesenchymal Transition (EMT) plays a critical role in the organism development, providing cell migration and tissue formation. However, its erroneous activation in malignancies can serve as the basis for the dissemination of cancer cells and metastasis. The Zeb1 transcription factor, which regulates the EMT activation, has been shown to play an essential role in malignant transformation. This factor is involved in many signaling pathways that influence a wide range of cellular functions via interacting with many proteins that affect its transcriptional functions. Importantly, the interactome of Zeb1 depends on the cellular context. Here, using the inducible expression of Zeb1 in epithelial breast cancer cells, we identified a substantial list of novel potential Zeb1 interaction partners, including proteins involved in the formation of malignant neoplasms, such as ATP-dependent RNA helicase DDX17and a component of the NURD repressor complex, CTBP2. We confirmed the presence of the selected interactors by immunoblotting with specific antibodies. Further, we demonstrated that co-expression of Zeb1 and CTBP2 in breast cancer patients correlated with the poor survival prognosis, thus signifying the functionality of the Zeb1–CTBP2 interaction.

Gynura divaricata Water Extract Presented the Possibility to Enhance Neuronal Regeneration

Gynura divaricata (GD) is an Asian herb widely used as an alternative medicine and functional food for type 2 diabetes. Diabetic neuropathy is considered as an important complication of diabetic patients. This study focused on neuroregenerative effects of GD for use in the prevention of diabetic neuropathy. GD leaves were cut and boiled in water to mimic real-life cooking. The boiled content was filtered through white gauze and lyophilized to preserve as dried powder. Antioxidant assay was performed using DPPH assays. UHPLC-QTOF-MS/MS was employed to test for important compounds in the extract of these herbs. MTT assay was used to test for cell viability. The extracts at concentration of 250 μg/mL were tested with human gingival cell to observe the change of gene expression. The DPPH assay showed that GD water extract at the concentration of 5000 μg/mL could inhibit DPPH radical for 39.2%. The results showed that 5000 µg of GD water extract contained total phenolic content equivalent to 310.9 µg standard gallic acid. UHPLC-QTOF-MS/MS result found phenolic acids and flavonoids as the main components. Human gingival cells treated with 250 μg/mL of GD water extract for 10 days showed upregulation of some neuronal differentiation markers. Staining with Cdr3 dye confirmed the presentation of neuronal progenitors. The extract at the concentration of 250 μg/mL was also tested with apical papilla cells to screen for change of gene expression by RNA sequencing. The result also showed significant upregulation of alpha-internexin (INA). These results indicated that GD water extract might have an inductive effect for neural regeneration and could be used as functional food and supplementation for the prevention or treatment of diabetic neuropathy. This work provided the basic knowledge for further investigations into the benefits of GD for diabetic neuropathy.

Zinc Finger E-Box Binding Homeobox 1 Regulates the Biological Behavior of Glioma Cells via iNOS/NF-κB Signaling

The gliomas pathogenesis is complex and effective molecular targets are still unclear. ZEB1 regulates epithelial mesenchymal transition (EMT) and participates in tumors. Our study intends to analyze ZEB1’s role in glioma cells. qRT-PCR detected ZEB1 mRNA expression in normal group and tumor group. ZEB1 siRNA was transfected into glioma cells followed by measuring ZEB1, E-cadherin and Vimentin expression, cell proliferation, Capase-3 activity as well as NF-κB and iNOS changes by immunoblotting. Upregulation of ZEB1 was found in glioma tumor tissue and correlated with glioma clinicopathological characteristics. Interfering with ZEB1 by siRNA significantly down-regulated ZEB1, inhibited cell proliferation, increased Capase-3 activity, down regulated NF-κB and iNOS proteins in glioma cells, elevated E-cadherin and decreased Vimentin level (P <0.05). ZEB1 down regulation in glioma cells can change the expression of NF-κB/iNOS, regulate cell apoptosis and inhibit cell proliferation, thereby delaying EMT process.

ZEB1: New advances in fibrosis and cancer

Zinc finger E-box binding homeobox 1 (ZEB1) is an important transcription factor in epithelial mesenchymal transition (EMT) which participates in the numerous life processes, such as embryonic development, fibrosis and tumor progression. ZEB1 has multiple functions in human body and plays a crucial part in some life processes. ZEB1 is vital for the formation and development of the organs in the embryonic period. The abnormal expression of ZEB1 is a predictor for the poor prognosis or the poor survival in several cancers. ZEB1 contributes to the occurrence of fibrosis, cancer and even chemoresistance. Some research is indicated that fibrosis is finally developed into the cancers. Therefore, ZEB1 is probably taken as a biomarker in fibrosis or cancer. In this review, it is predicted of the structure of ZEB1 and the protein binding sites of ZEB1 with some protein, and it is discussed about the roles of ZEB1 in fibrosis and cancer progression to elaborate the potential applications of ZEB1 in clinic.

Transcriptional profiles along cell programming into corneal epithelial differentiation

Using the rabbit corneal epithelial cell line RCE1(5T5) as a model, we analyzed three differentiation stages, distinguished on basis to the growth state of cultured cells and after studying the expression of transcription factors such as Oct4, Pax6 and ΔNp63α, selected differentiation markers, and signaling or epigenetic markers such as Notch receptors and Prdm3. Namely, proliferative non-differentiated cells, committed cells, and cells that constitute a stratified epithelium with a limbal epithelial-like structure. RNAseq based transcriptome analysis showed that 4891 genes were differentially expressed among these stages displaying distinctive gene signatures: proliferative cells had 1278 genes as gene signature, and seem to be early epithelial progenitors with an Oct4⁺, KLF4⁺, Myc⁺, ΔNp63α⁺, ABCG2⁺, Vimentin⁺, Zeb1⁺, VANGL1⁺, Krt3^-, Krt12^- phenotype. Committed cells had a gene signature with 417 genes and displayed markers indicative of the beginning of corneal differentiation, and genes characteristic of proliferative cells; we found the possible participation of Six3 and Six4 transcription factors along this stage. The third stage matches with a stratified corneal epithelium (gene signature comprising 979 genes) and is typified by an increase in the expression of WNT10A and NOTCH 2 and 3 signaling and Cux1 transcription factor, besides Pax6, KLF4 or Sox9. The differentiated cells express about 50% of the genes that belong to the Epidermal Differentiation Complex (EDC). Analysis of the differences between corneal epithelium and epidermis could be crucial to understand the regulatory mechanisms that lead to the expression of the differentiated phenotype.

The corepressor CtBP2 is required for proper development of the mouse cerebral cortex

The development of the cerebral cortex depends on numerous parameters, including extracellular cues and microenvironmental factors that also affect gene expression. C-Terminal Binding Proteins (CtBPs) 1 and 2 are transcriptional co-repressors which have been shown to be critically involved in embryonic development. CtBPs are oxygen sensing molecules, and we have previously demonstrated an important role for CtBP1 in integrating oxygen levels and BMP-signaling to influence neural progenitor fate choice. In turn, CtBP2 has been associated with neurodevelopment and neurological disease, and we have shown that CtBP2 acetylation and dimerization, required for proper transcriptional activity, are regulated by microenvironmental oxygen levels. Yet, the putative function of CtBP2 in mammalian cortical development and neurogenesis in vivo is still largely unknown. Here we show that CtBP2 was widely expressed by neural stem and progenitor cells (NSPCs) as well as neurons during cortical development in mice. By using in utero electroporation of siRNA to reduce the levels of CtBP2 mRNA and protein in the developing mouse brain, we found that the NSPC proliferation and migration were largely perturbed, while glial differentiation under these conditions remained unchanged. Our study provides evidence that CtBP2 is required for the maintenance and migration of the NSPCs during mouse cortical development.

Radial Glial Cell-Derived VCAM1 Regulates Cortical Angiogenesis Through Distinct Enrichments in the Proximal and Distal Radial Processes

Angiogenesis in the developing cerebral cortex accompanies cortical neurogenesis. However, the precise mechanisms underlying cortical angiogenesis at the embryonic stage remain largely unknown. Here, we show that radial glia-derived vascular cell adhesion molecule 1 (VCAM1) coordinates cortical vascularization through different enrichments in the proximal and distal radial glial processes. We found that VCAM1 was highly enriched around the blood vessels in the inner ventricular zone (VZ), preventing the ingrowth of blood vessels into the mitotic cell layer along the ventricular surface. Disrupting the enrichment of VCAM1 surrounding the blood vessels by a tetraspanin-blocking peptide or conditional deletion of Vcam1 gene in neural progenitor cells increased angiogenesis in the inner VZ. Conversely, VCAM1 expressed in the basal endfeet of radial glial processes promoted angiogenic sprouting from the perineural vascular plexus (PNVP). In utero, overexpression of VCAM1 increased the vessel density in the cortical plate, while knockdown of Vcam1 accomplished the opposite. In vitro, we observed that VCAM1 bidirectionally affected endothelial cell proliferation in a concentration-dependent manner. Taken together, our findings identify that distinct concentrations of VCAM1 around VZ blood vessels and the PNVP differently organize cortical angiogenesis during late embryogenesis.

SLUG Directs the Precursor State of Human Brain Tumor Stem Cells

In glioblastoma (GBM), brain tumor stem cells (BTSCs) encompass heterogenous populations of multipotent, self-renewing, and tumorigenic cells, which have been proposed to be at the root of therapeutic resistance and recurrence. While the functional significance of BTSC heterogeneity remains to be fully determined, we previously distinguished relatively quiescent stem-like precursor state from the more aggressive progenitor-like precursor state. In the present study, we hypothesized that progenitor-like BTSCs arise from stem-like precursors through a mesenchymal transition and drive post-treatment recurrence. We first demonstrate that progenitor-like BTSCs display a more mesenchymal transcriptomic profile. Moreover, we show that both mesenchymal GBMs and progenitor-like BTSCs are characterized by over-activated STAT3/EMT pathways and that SLUG is the primary epithelial to mesenchymal transition (EMT) transcription factor directly regulated by STAT3 in BTSCs. SLUG overexpression in BTSCs enhances invasiveness, promotes inflammation, and shortens survival. Importantly, SLUG overexpression in a quiescent stem-like BTSC line enhances tumorigenesis. Finally, we report that recurrence is associated with SLUG-induced transcriptional changes in both BTSCs and GBM patient samples. Collectively, our findings show that a STAT3-driven precursor state transition, mediated by SLUG, may prime BTSCs to initiate more aggressive mesenchymal recurrence. Targeting the STAT3/SLUG pathway may maintain BTSCs in a quiescent stem-like precursor state, delaying recurrence and improving survival in GBM.