The mandibular condyle is a critical growth center in craniofacial bone development, especially during postnatal stages. Postnatal condyle osteogenesis requires precise spatiotemporal coordination of growth factor signaling cascades and hierarchical gene regulatory networks. Plagl1, which encodes a zinc finger transcription factor, is a paternally expressed gene. We demonstrate that PLAGL1 is highly expressed in cranial neural crest cell (CNCC)-derived lineage cells in mouse condyles. Using the CNCC-derived lineage-specific Plagl1 knockout mouse model, we evaluate the function of PLAGL1 during postnatal mouse condyle development. Our findings show that PLAGL1 contributes significantly to osteoblast differentiation, and its deficiency impairs osteogenic lineage differentiation, which consequently disrupts mandibular condyle development. Mechanistically, insulin-like growth factor 2 (IGF2) in complex with IGF-binding proteins (IGFBPs) has been identified as the principal PLAGL1 effector responsible for osteogenic regulation during postnatal condyle morphogenesis. Plagl1 deficiency significantly downregulates the IGF2/IGFBP pathway, leading to disordered glucose metabolism, defective extracellular matrix organization, and impaired ossification. Exogenous IGF2 treatment rescues impaired osteoblast differentiation caused by Plagl1 deficiency. In conclusion, the PLAGL1-IGF2 axis is a critical regulator of osteogenesis during mandibular condyle development.
Animals ; Osteogenesis/genetics* ; Insulin-Like Growth Factor II/metabolism* ; Mice ; Transcription Factors/metabolism* ; Mice, Knockout ; Cell Differentiation ; DNA-Binding Proteins/genetics* ; Mandibular Condyle/growth & development* ; Osteoblasts/cytology* ; Signal Transduction ; Neural Crest/cytology*

Neural crest stem cells originated from hair follicle (epidermal neural crest stem cell, EPI-NCSC) are easy to obtain and have potentials to differentiate into various tissues, which make them eminent seed cells for tissue engineering. EPI-NCSC is now used to repair nerve injury, especially, the spinal cord injury. To investigate their effects on repairing peripheral nerve injury, EPI-NCSC from a GFP-SD rat were primarily cultured on coated dishes and on a poly lactic acid coglycolic acid copolymer (PLGA) membrane. Methyl thiazolyl tetrazolium (MTT) assay showed that the initial adhesion rate of EPI-NCSC was 89.7% on PLGA membrane, and the relative growth rates were 89.3%, 87.6%, 85.6%, and 96.6% on the 1st, 3rd, 5th, 7th day respectively. Cell cycles and DNA ploidy analysis demonstrated that cell cycles and proliferation indexes of cultured EPI-NCSC had the same variation pattern on coated dishes and PLGA membrane. Then cultured EPI-NCSC were mixed with equal amount of extracellular matrix and injected into a PLGA conduit to connect a 10 mm surgery excision gap of rat sciatic nerve, Dulbecco's Modified Eagle's medium (DMEM) was used to substitute EPI-NCSC in the control group. After four weeks of transplantation, the defected sciatic nerve achieved a histological restoration, the sensory function of rat hind limb was partly recovered and the sciatic nerve index was also improved. The above results showed that a PLGA conduit filled with EPI-NCSC has a good repair effect on the peripheral nerve injury.
Animals ; Cells, Cultured ; Neural Crest ; cytology ; Neural Stem Cells ; cytology ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; pathology ; Spinal Cord Injuries ; Stem Cell Transplantation ; Tissue Engineering

BACKGROUNDTbx1 is the major candidate gene for DiGeorge syndrome (DGS). Similar to defects observed in DGS patients, the structures disrupted in Tbx1(-/-) animal models are derived from the neural crest cells during development. Although the morphological phenotypes of some Tbx1 knock-down animal models have been well described, analysis of the cardiac performance is limited. Therefore, myocardial performance was explored in Tbx1 morpholino injected zebrafish embryos.

METHODSTo elucidate these issues, Tbx1 specific morpholino was used to reduce the function of Tbx1 in zebrafish. The differentiation of the myocardial cells was observed using whole mount in situ hybridization. Heart rates were observed and recorded under the microscope from 24 to 72 hours post fertilization (hpf). The cardiac performance was analyzed by measuring ventricular shortening fraction and atrial shortening fraction.

RESULTSTbx1 morpholino injected embryos were characterized by defects in the pharyngeal arches, otic vesicle, aortic arches and thymus. In addition, Tbx1 knock down reduced the amount of pharyngeal neural crest cells in zebrafish. Abnormal cardiac morphology was visible in nearly 20% of the Tbx1 morpholino injected embryos. The hearts in these embryos did not loop or loop incompletely. Importantly, cardiac performance and heart rate were reduced in Tbx1 morpholino injected embryos.

CONCLUSIONSTbx1 might play an essential role in the development of pharyngeal neural crest cells in zebrafish. Cardiac performance is impaired by Tbx1 knock down in zebrafish.

Animals ; Branchial Region ; cytology ; drug effects ; Heart ; drug effects ; physiology ; Heart Rate ; drug effects ; In Situ Hybridization ; Myocardium ; cytology ; Neural Crest ; cytology ; drug effects ; Oligonucleotides, Antisense ; pharmacology ; T-Box Domain Proteins ; antagonists & inhibitors ; metabolism ; Thymus Gland ; cytology ; drug effects ; Zebrafish ; embryology ; metabolism ; Zebrafish Proteins ; antagonists & inhibitors ; metabolism

Microtubules play important roles in mitotic spindle assembly and chromosome segregation to maintain normal cell cycle progression. A number of microtubule-associated proteins have been identified in epithelial and neural cell cultures; however, their physiological significance is not well characterized due to the lack of appropriate in vivo animal models. Nucleolar spindle-associated protein (NuSAP) is a microtubule-binding protein and is reported to be involved in mitosis by cell culture studies. In this report, we identified the zebrafish homologue of human NuSAP and investigated its expression profile and functions. Using in situ hybridization, we demonstrated that transcripts of zebrafish nusap1 are specifically expressed in the retina, forebrain, hindbrain and neural crest. When the in vivo expression of nusap1 was knocked down through antisense oligonucleotide morpholino technology, the morphants of nusap1 showed impaired morphogenesis in the trunk and yolk extension, implying the involvement of Nusap1 in cell migration. Mechanistic studies revealed that nusap1 morphants have an altered expression pattern of neural crest markers crestin and sox9b, but normal expression of blood vessel and notochord markers gata1 and shh. In addition, nusap1 mRNA injection caused serious apoptosis in retina and hindbrain tissue, and these phenotypes can be rescued by co-injection of morpholino against nusap1. These observations not only suggest a role for Nusap1 in connecting apoptosis with cell migration, but also provide strong evidences that Nusap1 is potentially involved in morphogenesis in vertebrates.
Amino Acid Sequence ; Animals ; Animals, Genetically Modified ; Apoptosis ; genetics ; physiology ; Base Sequence ; Cell Movement ; genetics ; physiology ; Cloning, Molecular ; DNA Primers ; genetics ; Gene Expression Profiling ; Gene Expression Regulation, Developmental ; Gene Knockdown Techniques ; Humans ; In Situ Hybridization ; Microtubule-Associated Proteins ; genetics ; physiology ; Molecular Sequence Data ; Neural Crest ; cytology ; embryology ; physiology ; Phylogeny ; Sequence Homology, Amino Acid ; Zebrafish ; embryology ; genetics ; Zebrafish Proteins ; genetics ; physiology

OBJECTIVETo investigate the effects of FGF-8 on cranial neural crest cell (CNCC) differentiating into ectomesenchymal cell of the first branchial arch, and determine the appropriate dose and stage of CNCC exposure to FGF-8.

METHODSCranial neural crest explants were cultured in free-serum medium containing modified DMEM/F12 and different doses of FGF-8. The differentiation type of CNCC were determined by in situ hybridization for Hoxa2 and immunocytochemistry for vimentin.

RESULTSPre-emigrating CNCC demonstrated the negative Hoxa2 stain and positive vimentin stain after treated by 100 ug/FGF-8. Both post-emigrating CNCC group and control group were positive for Hoxa2 and vimentin stain.

CONCLUSIONSOn the early stage of CNCC emigration, the first branchial arch phenotype of CNCC could be induced by FGF-8. This experiment could provide in vitro model for study on the mechanism of tooth-jaw regeneration.

Animals ; Branchial Region ; cytology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Cranial Nerves ; cytology ; Female ; Fibroblast Growth Factor 8 ; pharmacology ; Male ; Mesoderm ; cytology ; Mice ; Mice, Inbred Strains ; Neural Crest ; cytology

OBJECTIVEAccording to development biology, cranial neural crest stem cell (CNCSC) can differentiate into precursor cells of tooth, jaw and peripheral nerve system, but in vitro study is less reported. In the present study, CNCSC were dissociated and cultured in vitro, and the biological characteristics of CNCSC was investigated.

METHODSCranial neural tubes, dissected from mouse E9d, were explanted onto fibronectin-coated dishes. CNCSCs emigrated from the explanted neural tubes, cultured in a serum-free medium containing modified DMEM/F12. Biological characteristics of CNCSC were detected by morphology, nuclear labeled with BurdU and immunocytochemistry.

RESULTSFibroblast-like CNCSCs demonstrated the characteristics of stem cell, such as clonality, self-renewal and multipotentiality. The result of immunocytochemical stain showed that CNCSC expressed HNK-1 antigen.

CONCLUSIONCNCSC were cultured successfully, providing a experimental basis for study on tooth/jaw-like differentiation of CNCSC in vitro, especially providing a cell source for investigating tooth/jaw regeneration.

Animals ; Cell Differentiation ; Cranial Nerves ; cytology ; Female ; In Vitro Techniques ; Male ; Mice ; Neural Crest ; cytology ; Stem Cells ; cytology