scholarly journals Fgf/Ets signalling in Xenopus ectoderm initiates neural induction and patterning in an autonomous and paracrine manners

2020 ◽  
Author(s):  
Ikuko Hongo ◽  
Harumasa Okamoto
Keyword(s):  
Neural Development ◽  
Neural Induction ◽  
Dominant Negative ◽  
Neural Patterning ◽  
Paracrine Signalling ◽  
Neural Genes ◽  
Morphogenetic Protein ◽  
Bmp Signalling

ABSTRACTFibroblast growth factor (Fgf) and anti-bone morphogenetic protein (Bmp) signals are derived from the organiser of mesoderm origin and cooperate to promote Xenopus neural development from the gastrula ectoderm. Using antisense oligos to Fgf2 and Fgf8 and dominant-negative Ets transcription factors, we showed that the expression of Fgf2, Fgf8, and Ets in ectoderm cells is essential to initiate neural induction both in vivo and in vitro. Our findings show that neural induction is initiated primarily by autonomous signalling in ectoderm cells, rather than by paracrine signalling from organiser cells. The signalling in ectoderm cells is transduced via the Fgf/Ras/Mapk/Ets pathway, independent of Bmp signal inhibition via the Fgf/Ras/Mapk/Smad1 route, as indicated by earlier studies. Through the same pathway, Fgfs activated position-specific neural genes dose-dependently along the anteroposterior axis in cultured ectoderm cells. The expression of these genes coincides with the establishment of the activated Ets gradient within the gastrula ectoderm. Organiser cells, being located posteriorly to the ectoderm, secrete Fgfs as gastrulation proceeds, which among several candidate molecules initially promote neural patterning of the induced neuroectoderm as morphogens.Summary statementFgf/Ets signalling in ectodermal cells is required to initiate the expression of both anterior and posterior neural genes from the late blastula to gastrula stages, independent of anti-Bmp signalling.

Transgenic Xenopus embryos from sperm nuclear transplantations reveal FGF signaling requirements during gastrulation

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 3173-3183 ◽  
Author(s):  
K.L. Kroll ◽  
E. Amaya
Keyword(s):  
Large Scale ◽  
Neural Induction ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Mesoderm Induction ◽  
Fgf Signaling ◽  
Fgf Receptor ◽  
Transgenic Expression

We have developed a simple approach for large-scale transgenesis in Xenopus laevis embryos and have used this method to identify in vivo requirements for FGF signaling during gastrulation. Plasmids are introduced into decondensed sperm nuclei in vitro using restriction enzyme-mediated integration (REMI). Transplantation of these nuclei into unfertilized eggs yields hundreds of normal, diploid embryos per day which develop to advanced stages and express integrated plasmids nonmosaically. Transgenic expression of a dominant negative mutant of the FGF receptor (XFD) after the mid-blastula stage uncouples mesoderm induction, which is normal, from maintenance of mesodermal markers, which is lost during gastrulation. By contrast, embryos expressing XFD contain well-patterned nervous systems despite a putative role for FGF in neural induction.

scholarly journals The Therapeutic Effect of Extracellular Vesicles on Asthma in Pre-Clinical Models: A Systematic Review Protocol

2021 ◽  
Vol 1 (1) ◽  
pp. 84-95
Author(s):  
Patience O. Obi ◽  
Jennifer E. Kent ◽  
Maya M. Jeyaraman ◽  
Nicole Askin ◽  
Taiana M. Pierdoná ◽  
...  
Keyword(s):  
Systematic Review ◽  
Extracellular Vesicles ◽  
Current Knowledge ◽  
Grey Literature ◽  
Specific Treatment ◽  
Therapeutic Effects ◽  
Management Options ◽  
Paracrine Signalling

Asthma is the most common pediatric disease, characterized by chronic airway inflammation and airway hyperresponsiveness. There are several management options for asthma, but no specific treatment. Extracellular vesicles (EVs) are powerful cellular mediators of endocrine, autocrine and paracrine signalling, and can modulate biophysiological function in vitro and in vivo. A thorough investigation of therapeutic effects of EVs in asthma has not been conducted. Therefore, this systematic review is designed to synthesize recent literature on the therapeutic effects of EVs on physiological and biological outcomes of asthma in pre-clinical studies. An electronic search of Web of Science, EMBASE, MEDLINE, and Scopus will be conducted on manuscripts published in the last five years that adhere to standardized guidelines for EV research. Grey literature will also be included. Two reviewers will independently screen the selected studies for title and abstract, and full text based on the eligibility criteria. Data will be extracted, narratively synthesized and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This systematic review will summarize the current knowledge from preclinical studies investigating the therapeutic effects of EVs on asthma. The results will delineate whether EVs can mitigate biological hallmarks of asthma, and if so, describe the underlying mechanisms involved in the process. This insight is crucial for identifying key pathways that can be targeted to alleviate the burden of asthma. The data will also reveal the origin, dosage and biophysical characteristics of beneficial EVs. Overall, our results will provide a scaffold for future intervention and translational studies on asthma treatment.

scholarly journals O80: GREMLIN-1 PROMOTES TUMOURIGENESIS AND METASTASIS IN HER2 POSITIVE BREAST CANCER

2021 ◽  
Vol 108 (Supplement_1) ◽  
Author(s):  
C Zabkiewicz ◽  
L Ye ◽  
R Hargest
Keyword(s):  
Breast Cancer ◽  
Cellular Growth ◽  
Breast Cancers ◽  
Her2 Positive ◽  
Mesenchymal Transition ◽  
Her2 Breast Cancer ◽  
Bmp Signalling ◽  
Gremlin 1

Abstract Introduction HER2 over-expression denotes poor prognosis in breast cancers.Bone morphogenetic protein(BMP) signalling is known to interact with EGF signalling, co-regulating breast cancer progression.BMP antagonist Gremlin-1 may influence breast cancer disease progression, but this remains unexplored in HER2 positive breast cancers. Method GREM1 and HER2 expression, and clinical outcomes were examined in clinical cohorts.GREM1 overexpression or pEF control plasmid were transduced into BT474 HER2+breast cancer cells. In vitro function tests using BT474 pEF and BT474GREM1cells include 2D/3D growth, migration, and expression of epithelial to mesenchymal transition(EMT)markers. Signalling cascades were examined in BT474 treated with RhGremlin-1. In vivo, BALB/c nude mice underwent either mammary injection or intra-cardiac injection of BT474pEF or BT474GREM1 cells and disease burden assessed. Result GREM1 expression correlates with HER2 in breast tumours(p=0.03) and is higher in metastatic HER2 positive cancers (p = 0.04). HER2 positive patients with high GREM1 have poor survival(p = 0.0002). BT474GREM1cells have up-regulated markers of EMT compared to control. BT474 RhGremlin-1 treated cells have active AKT pathway signalling, independent of BMP signalling. In vitro,  BT474GREM1cells significantly proliferate and migrate compared to control(p<0.05 and p < 0.001).This is confirmed in vivo,  BT474GREM1 mice grew significantly larger mammary tumours(p<0.05) and had more PETCT metastatic hotspots. Conclusion Gremlin-1 is correlated with poor outcomes in HER2 patients and promotes breast cancer cellular growth, migration and metastasis.Gremlin-1 is a novel area of research with potential as a prognostic biomarker and therapeutic target for personalised, effective, breast cancer outcomes. Take-home message BMP antagonists are gaining interest for their potential in breast cancer prognosis and therapeutics.This novel area of research shows BMP antagonist Gremlin-1 is of importance in HER2 positive breast cancers. DRAGONS DEN

scholarly journals The Bone Regeneration Capacity of BMP-2 + MMP-10 Loaded Scaffolds Depends on the Tissue Status

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 979
Author(s):  
Patricia Garcia-Garcia ◽  
Ricardo Reyes ◽  
José Antonio Rodriguez ◽  
Tomas Martín ◽  
Carmen Evora ◽  
...  
Keyword(s):  
Bone Formation ◽  
Bone Regeneration ◽  
Growth Promotion ◽  
Tissue Growth ◽  
Bone Morphogenetic Protein 2 ◽  
Morphogenetic Protein ◽  
Therapeutic Molecules ◽  
Positive Effect

Biomaterials-mediated bone formation in osteoporosis (OP) is challenging as it requires tissue growth promotion and adequate mineralization. Based on our previous findings, the development of scaffolds combining bone morphogenetic protein 2 (BMP-2) and matrix metalloproteinase 10 (MMP-10) shows promise for OP management. To test our hypothesis, scaffolds containing BMP-2 + MMP-10 at variable ratios or BMP-2 + Alendronate (ALD) were prepared. Systems were characterized and tested in vitro on healthy and OP mesenchymal stem cells and in vivo bone formation was studied on healthy and OP animals. Therapeutic molecules were efficiently encapsulated into PLGA microspheres and embedded into chitosan foams. The use of PLGA (poly(lactic-co-glycolic acid)) microspheres as therapeutic molecule reservoirs allowed them to achieve an in vitro and in vivo controlled release. A beneficial effect on the alkaline phosphatase activity of non-OP cells was observed for both combinations when compared with BMP-2 alone. This effect was not detected on OP cells where all treatments promoted a similar increase in ALP activity compared with control. The in vivo results indicated a positive effect of the BMP-2 + MMP-10 combination at both of the doses tested on tissue repair for OP mice while it had the opposite effect on non-OP animals. This fact can be explained by the scaffold’s slow-release rate and degradation that could be beneficial for delayed bone regeneration conditions but had the reverse effect on healthy animals. Therefore, the development of adequate scaffolds for bone regeneration requires consideration of the tissue catabolic/anabolic balance to obtain biomaterials with degradation/release behaviors suited for the existing tissue status.

BMP2 Is Required for Postnatal Maintenance of Osteochondral Tissues of the Temporomandibular Joint

Cartilage ◽  
2020 ◽  
pp. 194760352098015
Author(s):  
Mara H. O’Brien ◽  
Eliane H. Dutra ◽  
Shivam Mehta ◽  
Po-Jung Chen ◽  
Sumit Yadav
Keyword(s):  
Age Groups ◽  
Mandibular Condyle ◽  
Bone Morphogenetic Protein 2 ◽  
Matrix Synthesis ◽  
Cartilage Growth ◽  
Chondrocyte Proliferation ◽  
Conditional Deletion ◽  
Morphogenetic Protein

Objective Bone morphogenetic protein 2 (BMP2) plays important roles in cartilage growth and development. Paradoxically, elevated levels of BMP2 leads to hypertrophic differentiation and osteoarthritis of cartilage. We examined the in vivo loss of BMP2 in cells expressing aggrecan of the mandibular condyle and knee. Design Three-week-old BMP2 flox/flox- CreER-positive mice and their Cre-negative littermates were treated with tamoxifen and raised until 3 or 6 months. We also investigated the direct effects of BMP2 on chondrocytes in vitro. Cells from the mandibular condyle of mice were treated with recombinant human BMP2 (rhBMP2) or rhNoggin (inhibitor of BMP2 signaling). Results Conditional deletion of BMP2 caused breakage of the cartilage integrity in the mandibular condyle of mice from both age groups, accompanied by a decrease in cartilage thickness, matrix synthesis, mineralization, chondrocyte proliferation, and increased expression of degeneration markers, while the effects at articular cartilage were not significant. In vitro results revealed that rhBMP2 increased chondrocyte proliferation, mineralization, and differentiation, while noggin induced opposite effects. Conclusions In conclusion, BMP2 is essential for postnatal maintenance of the osteochondral tissues of the mandibular condyle.

scholarly journals Human Keratinocytes Adopt Neuronal Fates After In Utero Transplantation in the Developing Rat Brain

2021 ◽  
Vol 30 ◽  
pp. 096368972097821
Author(s):  
Andrea Tenorio-Mina ◽  
Daniel Cortés ◽  
Joel Esquivel-Estudillo ◽  
Adolfo López-Ornelas ◽  
Alejandro Cabrera-Wrooman ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Ectopic Expression ◽  
Neural Induction ◽  
Human Keratinocytes ◽  
Differentiation Potential ◽  
Neuronal Proteins ◽  
Green Fluorescent

Human skin contains keratinocytes in the epidermis. Such cells share their ectodermal origin with the central nervous system (CNS). Recent studies have demonstrated that terminally differentiated somatic cells can adopt a pluripotent state, or can directly convert its phenotype to neurons, after ectopic expression of transcription factors. In this article we tested the hypothesis that human keratinocytes can adopt neural fates after culturing them in suspension with a neural medium. Initially, keratinocytes expressed Keratins and Vimentin. After neural induction, transcriptional upregulation of NESTIN, SOX2, VIMENTIN, SOX1, and MUSASHI1 was observed, concomitant with significant increases in NESTIN detected by immunostaining. However, in vitro differentiation did not yield the expression of neuronal or astrocytic markers. We tested the differentiation potential of control and neural-induced keratinocytes by grafting them in the developing CNS of rats, through ultrasound-guided injection. For this purpose, keratinocytes were transduced with lentivirus that contained the coding sequence of green fluorescent protein. Cell sorting was employed to select cells with high fluorescence. Unexpectedly, 4 days after grafting these cells in the ventricles, both control and neural-induced cells expressed green fluorescent protein together with the neuronal proteins βIII-Tubulin and Microtubule-Associated Protein 2. These results support the notion that in vivo environment provides appropriate signals to evaluate the neuronal differentiation potential of keratinocytes or other non-neural cell populations.

scholarly journals The Diagnostic Journey of a Patient with Prader–Willi-Like Syndrome and a Unique Homozygous SNURF-SNRPN Variant; Bio-Molecular Analysis and Review of the Literature

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 875
Author(s):  
Karlijn Pellikaan ◽  
Geeske M. van Woerden ◽  
Lotte Kleinendorst ◽  
Anna G. W. Rosenberg ◽  
Bernhard Horsthemke ◽  
...  
Keyword(s):  
Intellectual Disability ◽  
Single Nucleotide Polymorphism Array ◽  
Genetic Defect ◽  
Missense Variant ◽  
Dominant Negative ◽  
Dominant Negative Effect ◽  
Pituitary Hormone ◽  
Negative Effect

Prader–Willi syndrome (PWS) is a rare genetic condition characterized by hypotonia, intellectual disability, and hypothalamic dysfunction, causing pituitary hormone deficiencies and hyperphagia, ultimately leading to obesity. PWS is most often caused by the loss of expression of a cluster of genes on chromosome 15q11.2-13. Patients with Prader–Willi-like syndrome (PWLS) display features of the PWS phenotype without a classical PWS genetic defect. We describe a 46-year-old patient with PWLS, including hypotonia, intellectual disability, hyperphagia, and pituitary hormone deficiencies. Routine genetic tests for PWS were normal, but a homozygous missense variant NM_003097.3(SNRPN):c.193C>T, p.(Arg65Trp) was identified. Single nucleotide polymorphism array showed several large regions of homozygosity, caused by high-grade consanguinity between the parents. Our functional analysis, the ‘Pipeline for Rapid in silico, in vivo, in vitro Screening of Mutations’ (PRiSM) screen, showed that overexpression of SNRPN-p.Arg65Trp had a dominant negative effect, strongly suggesting pathogenicity. However, it could not be confirmed that the variant was responsible for the phenotype of the patient. In conclusion, we present a unique homozygous missense variant in SNURF-SNRPN in a patient with PWLS. We describe the diagnostic trajectory of this patient and the possible contributors to her phenotype in light of the current literature on the genotype–phenotype relationship in PWS.

scholarly journals Extracellular Signal-Regulated Kinase Binds to TFII-I and Regulates Its Activation of the c-fosPromoter

2000 ◽  
Vol 20 (4) ◽  
pp. 1140-1148 ◽  
Author(s):  
Dae-Won Kim ◽  
Brent H. Cochran
Keyword(s):  
Map Kinase ◽  
Transcriptional Activation ◽  
Dominant Negative ◽  
Binding Motif ◽  
Dependent Manner ◽  
Consensus Map ◽  
Interaction Domain ◽  
Extracellular Signal

ABSTRACT We have previously shown that TFII-I enhances transcriptional activation of the c-fos promoter through interactions with upstream elements in a signal-dependent manner. Here we demonstrate that activated Ras and RhoA synergize with TFII-I for c-fospromoter activation, whereas dominant-negative Ras and RhoA inhibit these effects of TFII-I. The Mek1 inhibitor, PD98059 abrogates the enhancement of the c-fos promoter by TFII-I, indicating that TFII-I function is dependent on an active mitogen-activated protein (MAP) kinase pathway. Analysis of the TFII-I protein sequence revealed that TFII-I contains a consensus MAP kinase interaction domain (D box). Consistent with this, we have found that TFII-I forms an in vivo complex with extracellular signal-related kinase (ERK). Point mutations within the consensus MAP kinase binding motif of TFII-I inhibit its ability to bind ERK and its ability to enhance the c-fos promoter. Therefore, the D box of TFII-I is required for its activity on the c-fos promoter. Moreover, the interaction between TFII-I and ERK can be regulated. Serum stimulation enhances complex formation between TFII-I and ERK, and dominant-negative Ras abrogates this interaction. In addition, TFII-I can be phosphorylated in vitro by ERK and mutation of consensus MAP kinase substrate sites at serines 627 and 633 impairs the phosphorylation of TFII-I by ERK and its activity on the c-fos promoter. These results suggest that ERK regulates the activity of TFII-I by direct phosphorylation.

scholarly journals Dominant-Negative FADD Rescues the In Vivo Fitness of a Cytomegalovirus Lacking an Antiapoptotic Viral Gene

2007 ◽  
Vol 82 (5) ◽  
pp. 2056-2064 ◽  
Author(s):  
Luka Čičin-Šain ◽  
Zsolt Ruzsics ◽  
Juergen Podlech ◽  
Ivan Bubić ◽  
Carine Menard ◽  
...  
Keyword(s):  
Virus Replication ◽  
Control Cell ◽  
Death Receptor ◽  
Formal Proof ◽  
Dominant Negative ◽  
Viral Fitness ◽  
Viral Gene ◽  
Apoptosis Inhibition

ABSTRACT Genes that inhibit apoptosis have been described for many DNA viruses. Herpesviruses often contain even more than one gene to control cell death. Apoptosis inhibition by viral genes is postulated to contribute to viral fitness, although a formal proof is pending. To address this question, we studied the mouse cytomegalovirus (MCMV) protein M36, which binds to caspase-8 and blocks death receptor-induced apoptosis. The growth of MCMV recombinants lacking M36 (ΔM36) was attenuated in vitro and in vivo. In vitro, caspase inhibition by zVAD-fmk blocked apoptosis in ΔM36-infected macrophages and rescued the growth of the mutant. In vivo, ΔM36 infection foci in liver tissue contained significantly more apoptotic hepatocytes and Kupffer cells than did revertant virus foci, and apoptosis occurred during the early phase of virus replication prior to virion assembly. To further delineate the mode of M36 function, we replaced the M36 gene with a dominant-negative FADD (FADDDN) in an MCMV recombinant. FADDDN was expressed in cells infected with the recombinant and blocked the death-receptor pathway, replacing the antiapoptotic function of M36. Most importantly, FADDDN rescued ΔM36 virus replication, both in vitro and in vivo. These findings have identified the biological role of M36 and define apoptosis inhibition as a key determinant of viral fitness.

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