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Fulltext Epithelial fusion during neural tube morphogenesis

Pai YJ, Abdullah NL, Mohd-Zin SW, Mohammed RS, Rolo A, Greene ND, et al.

Birth Defects Res. Part A Clin. Mol. Teratol., 2012 Oct;94(10):817-23.
PMID: 22945349 DOI: 10.1002/bdra.23072

Adhesion and fusion of epithelial sheets marks the completion of many morphogenetic events during embryogenesis. Neural tube closure involves an epithelial fusion sequence in which the apposing neural folds adhere initially via cellular protrusions, proceed to a more stable union, and subsequently undergo remodeling of the epithelial structures to yield a separate neural tube roof plate and overlying nonneural ectoderm. Cellular protrusions comprise lamellipodia and filopodia, and studies in several different systems emphasize the critical role of RhoGTPases in their regulation. How epithelia establish initial adhesion is poorly understood but, in neurulation, may involve interactions between EphA receptors and their ephrinA ligands. Epithelial remodeling is spatially and temporally correlated with apoptosis in the dorsal neural tube midline, but experimental inhibition of this cell death does not prevent fusion and remodeling. A variety of molecular signaling systems have been implicated in the late events of morphogenesis, but genetic redundancy, for example among the integrins and laminins, makes identification of the critical players challenging. An improved understanding of epithelial fusion can provide insights into normal developmental processes and may also indicate the mode of origin of clinically important birth defects.

Matched MeSH terms: Neural Crest/cytology; Neural Crest/embryology*; Neural Crest/metabolism
Fulltext Angiogenic and osteogenic potentials of dental stem cells in bone tissue engineering

Yusof MFH, Zahari W, Hashim SNM, Osman ZF, Chandra H, Kannan TP, et al.

J Oral Biol Craniofac Res, 2017 10 19;8(1):48-53.
PMID: 29556464 DOI: 10.1016/j.jobcr.2017.10.003

Manipulation of dental stem cells (DSCs) using current technologies in tissue engineering unveil promising prospect in regenerative medicine. DSCs have shown to possess angiogenic and osteogenic potential in both in vivo and in vitro. Neural crest derived DSCs can successfully be isolated from various dental tissues, exploiting their intrinsic great differentiation potential. In this article, researcher team intent to review the characteristics of DSCs, with focus on their angiogenic and osteogenic differentiation lineage. Clinical data on DSCs are still lacking to prove their restorative abilities despite extensive contemporary literature, warranting research to further validate their application for bone tissue engineering.

Matched MeSH terms: Neural Crest
Decellularized Matrix Derived from Neural Differentiation of Embryonic Stem Cells Enhances the Neurogenic Potential of Dental Follicle Stem Cells

Heng BC, Gong T, Wang S, Lim LW, Wu W, Zhang C

J Endod, 2017 Mar;43(3):409-416.
PMID: 28231979 DOI: 10.1016/j.joen.2016.10.033

INTRODUCTION: Dental follicle stem cells (DFSCs) possess neurogenic potential because they originate from the embryonic neural crest. This study investigated whether neural differentiation of DFSCs can be enhanced by culture on decellularized matrix substrata (NSC-DECM) derived from neurogenesis of human embryonic stem cells (hESCs).
METHODS: The hESCs were differentiated into neural stem cells (NSCs), and NSC-DECM was extracted from confluent monolayers of NSCs through treatment with deionized water. DFSCs seeded on NSC-DECM, Geltrex, and tissue culture polystyrene (TCPS) were subjected to neural induction during a period of 21 days. Expression of early/intermediate (Musashi1, PAX6, NSE, and βIII-tubulin) and mature/late (NGN2, NeuN, NFM, and MASH1) neural markers by DFSCs was analyzed at the 7-, 14-, and 21-day time points with quantitative real-time polymerase chain reaction. Immunocytochemistry for detection of βIII-tubulin, PAX6, and NGN2 expression by DFSCs on day 7 of neural induction was also carried out.
RESULTS: Quantitative RT-PCR showed that expression of PAX6, Musashi1, βIII-tubulin, NSE, NGN2, and NFM by DFSCs was enhanced on NSC-DECM versus either the Geltrex or TCPS groups. Immunocytochemistry showed that DFSCs in the NSC-DECM group displayed more intense staining for βIII-tubulin, PAX6, and NGN2 expression, together with more neurite outgrowths and elongated morphology, as compared with either Geltrex or TCPS.
CONCLUSIONS: DECM derived from neurogenesis of hESCs can enhance the neurogenic potential of DFSCs.

Matched MeSH terms: Neural Crest/cytology
Fulltext Bilateral Carotid Body Tumours

Amran, A.R., Jayaram, G., Kumar, G.

International Medical Journal Malaysia, 2006;5(1):1-6.
MyJurnal

Paragangliomas are slow growing hypervascular tumour arising from neural crest cell derivatives throughout the body. In the head and neck region, the major paraganglial cells are located at the carotid bifurcation (carotid body), along the ganglia of the vagus nerve and along the nerves supplying the middle ear and jugular bulb. Less common locations include the larynx, orbit, nose and the aortic arch. Carotid body tumours are very rare neoplasms constituting less than 0.5% of all tumours. The true nature of the tumour is established at the time of attempted biopsy or surgical resection, sometimes with disastrous consequences. Only a few of the more than 500 cases reported in the literature have been studied and diagnosed preoperatively. These tumours must be considered in the evaluation of any lateral neck mass, even one located far from the carotid bifurcation. We report a case of bilateral carotid body tumours detected using 16-slice MDHCT in a patient who presented with pulsatile neck swelling for two years. This tumour is rarely malignant; however it produces serious problems by its progressive enlargement and impairment of adjacent structures in the neck. The treatment of choice is surgical resection; preferably to excise this lesion when it is small, because large, very vascular tumours are intimately attached to the carotid vessels and make surgical resection more hazardous. Pre-operative embolization can be performed in large tumours, as to facilitates surgery and reduce complication. In most of the cases, there is strong attachment of the tumour to the carotid arteries. When this is the situation, removal of the tumour means complete excision of both great arteries as well, and the mortality rate is 40 to 45 %. When surgical removal is not feasible, radiotherapy may help to control the tumour growth, although the results have not been encouraging. As it is very slow growing tumour with the growth rate of less than 5 mm per year tumours in old patients with significant risk factors for surgical intervention can be managed by observation alone.

Matched MeSH terms: Neural Crest
Fulltext A Novel Occulta-Type Spina Bifida Mediated by Murine Double Heterozygotes EphA2 and EphA4 Receptor Tyrosine Kinases

Abdullah NL, Mohd-Zin SW, Ahmad-Annuar A, Abdul-Aziz NM

Front Cell Dev Biol, 2017;5:105.
PMID: 29312933 DOI: 10.3389/fcell.2017.00105

Members of the Eph receptor tyrosine kinase have previously been implicated in cranial neural tube development. Failure of neural tube closure leads to the devastating conditions known as anencephaly and spina bifida. EphA2 and EphA4 are expressed at the tips of the closing spinal neural folds prior and during neural tube closure. We investigated the possible role of murine EphA2 and EphA4 during the last step of primary neural tube closure, which is adhesion and fusion. The individual mouse knockouts of EphA2 and EphA4 per se do not exhibit neural tube defects (NTDs). The embryos generated by the crossing of double heterozygotes Epha2tm1Jrui/+Epha4rb-2J/+ displayed NTDs with a wide degree of severity including close exencephaly and close spina bifida (spina bifida occulta). Interestingly, mutants displaying NTDs had skin covering the underlying lesion. The tissue sections revealed the elevated neural folds had not adhered and fused. The phenotypes seen in Epha2tm1Jrui/+Epha4rb-2J/+ double heterozygous embryos suggest both genes play a compensatory role with each other in the adhesion and fusion of the neural tube. In this study, there exists a >50% penetrance of NTDs in the mouse mutants, which genetically have a single allele each of EphA2 and EphA4 absent.

Matched MeSH terms: Neural Crest
Fulltext EphrinB2 signalling modulates the neural differentiation of human dental pulp stem cells

Heng BC, Gong T, Xu J, Lim LW, Zhang C

Biomed Rep, 2018 Aug;9(2):161-168.
PMID: 29963307 DOI: 10.3892/br.2018.1108

Dental pulp stem cells (DPSCs) originate from the embryonic neural crest and have neurogenic potential. The present study investigated the roles of the forward and reverse EphrinB2 signalling pathways during DPSC neurogenesis. Treatment of DPSCs with recombinant EphrinB2-Fc protein over 7 days in a neural induction culture resulted in significant downregulation of the following neural markers: βIII-Tubulin, neural cell adhesion molecule (NCAM), nestin, neurogenin 2 (NGN2), neurofilament medium polypeptide and Musashi1. Immunocytochemistry revealed that EphrinB2-Fc-treated DPSCs exhibited more rounded morphologies with fewer neurite outgrowths as well as reduced protein expression of βIII-tubulin and NGN2. Treatment of DPSCs with a peptide inhibitor specific to the EphB4 receptor significantly upregulated expression of the neural markers microtubule-associated protein 2, Musashi1, NGN2 and neuron-specific enolase, whereas treatment with a peptide inhibitor specific to the EphB2 receptor exerted negligible effects on neurogenesis. Transgenic expression of EphrinB2 in DPSCs resulted in significant upregulation of Musashi1 and NCAM gene expression, while treatment of DPSCs with recombinant EphB4-Fc protein led to significant upregulation of only Musashi1. Thus, it may be concluded that stimulation of forward EphrinB2-EphB4 signalling markedly inhibited neurogenesis in DPSCs, whereas suppression of this forward signalling pathway with peptide inhibitor specific to EphB4 promoted neurogenesis. Meanwhile, stimulation of reverse EphB4-EphrinB2 signalling only marginally enhanced the neural differentiation of DPSCs. The present findings indicate the potential application of peptide or small molecule inhibitors of EphrinB2 forward signalling in neural tissue engineering with DPSCs.

Matched MeSH terms: Neural Crest
Mutated Shiitake extracts inhibit melanin-producing neural crest-derived cells in zebrafish embryo

Mahmood I, Azfaralariff A, Mohamad A, Airianah OB, Law D, Dyari HRE, et al.

Comp Biochem Physiol C Toxicol Pharmacol, 2021 Jul;245:109033.
PMID: 33737223 DOI: 10.1016/j.cbpc.2021.109033

The ability of natural extracts to inhibit melanocyte activity is of great interest to researchers. This study evaluates and explores the ability of mutated Shiitake (A37) and wildtype Shiitake (WE) extract to inhibit this activity. Several properties such as total phenolic (TPC) and total flavonoid content (TFC), antioxidant activity, effect on cell and component profiling were conducted. While having no significant differences in total phenolic content, mutation resulted in A37 having a TFC content (1.04 ± 0.7 mg/100 ml) compared to WE (0.86 ± 0.9 mg/100 ml). Despite that, A37 extract has lower antioxidant activity (EC50, A37 = 549.6 ± 2.70 μg/ml) than WE (EC50 = 52.8 ± 1.19 μg/ml). Toxicity tests on zebrafish embryos show that both extracts, stop the embryogenesis process when the concentration used exceeds 900 μg/ml. Although both extracts showed pigmentation reduction in zebrafish embryos, A37 extract showed no effect on embryo heartbeat. Cell cycle studies revealed that WE significantly affect the cell cycle while A37 not. Further tests found that these extracts inhibit the phosphorylation of Glycogen synthase kinase 3 β (pGSK3β) in HS27 cell line, which may explain the activation of apoptosis in melanin-producing cells. It was found that from 19 known compounds, 14 compounds were present in both WE and A37 extracts. Interestingly, the presence of decitabine in A37 extract makes it very potential for use in the medical application such as treatment of melanoma, skin therapy and even cancer.

Matched MeSH terms: Neural Crest/drug effects*
Fulltext Emerging Pathogenic and Prognostic Significance of Paired Box 3 (PAX3) Protein in Adult Gliomas

Angelopoulou E, Paudel YN, Piperi C

Transl Oncol, 2019 Jul 25;12(10):1357-1363.
PMID: 31352198 DOI: 10.1016/j.tranon.2019.07.001

Gliomas present the most common type of brain tumors in adults, characterized by high morbidity and mortality. In search of potential molecular targets, members of paired box (PAX) family have been found expressed in neural crest cells, regulating their proliferation, apoptosis, migration and differentiation. Recently, PAX3 overexpression has been implicated in glioma tumorigenesis by enhancing proliferation, increasing invasiveness and inducing resistance to apoptosis of glioma cells, while maintaining brain glioma stem cells (BGSCs) stemness. Although the oncogenic potential of PAX3 in gliomas is still under investigation, experimental evidence suggests that PAX3 function is mainly mediated through the canonical and non-canonical Wnt signaling pathway as well as through its interaction with GFAP and p53 proteins. In addition, PAX3 may contribute to the chemoresistance of glioma cells and modulates the effectiveness of novel experimental therapies. Further evidence indicates that PAX3 may represent a novel diagnostic and prognostic biomarker for gliomas, facilitating personalized treatment. This review addresses the emerging role of PAX3 in glioma diagnosis, prognosis and treatment, aiming to shed more light on the underlying molecular mechanisms that could lead to more effective treatment approaches.

Matched MeSH terms: Neural Crest