alcian-blue and Craniofacial-Abnormalities

Tributyltin (TBT) is a ubiquitous marine environmental contaminant, which has been known to cause axial skeletal deformities in fish embryos. However, the effects of TBT on the craniofacial cartilage development of fishes remain unclear. The present study was designed to investigate the effects of waterborne TBT at environmental levels (0, 0.1, 1, and 10 ng L(-1) as Sn) on craniofacial cartilage development in embryos of the rockfish (Sebastiscus marmoratus). Our study showed that TBT exposure induced craniofacial skeletal deformities, such as reduction of the craniofacial skeleton elements and a shorter lower jaw. The expressions of retinoic acid receptor α, sonic hedgehog, and proliferating cell nuclear antigen were depressed and the expressions of vitamin D receptor were increased in the rockfish embryos after TBT exposure. In addition, the activities of Ca(2+)-ATPase were inhibited after TBT exposure. These results suggested that TBT might perturb the proliferation and differentiation of chondrocytes, and disturb calcium homeostasis, thus disorganizing craniofacial skeletal development.

Topics: Alcian Blue; Analysis of Variance; Animals; Calcium; Cartilage; Chondrocytes; Craniofacial Abnormalities; DNA Primers; Dose-Response Relationship, Drug; Embryo, Nonmammalian; Fishes; Hedgehog Proteins; Proliferating Cell Nuclear Antigen; Real-Time Polymerase Chain Reaction; Receptors, Retinoic Acid; Retinoic Acid Receptor alpha; Trialkyltin Compounds; Water Pollutants, Chemical

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants, which are known carcinogens and teratogens. However, the toxicity of PAHs during skeletal development and the mechanism involved are not completely clear. In the present study, rockfish (Sebastiscus marmoratus) embryos were exposed to pyrene (Pyr) for 7 days at 0.5, 5 and 50 nM which resulted in craniofacial skeleton deformities. Pyr exposure for 6 days reduced the expression of PCNA, Col2a1 and Sox9 in the craniofacial skeleton revealed using in situ hybridization. These results suggest that Pyr exposure impairs skeleton development via disrupting the proliferation of the chondrocytes. At the same time, Pyr exposure reduced the expression of lox1 and inhibited the activity of lysyl oxidase, which is the key enzyme controlling the collagen cross-linking, and which might therefore have been one of the reasons for the deformative Meckel's cartilage (lower jaw).

Topics: Alcian Blue; Analysis of Variance; Animals; Base Sequence; Chondrocytes; Collagen Type II; Craniofacial Abnormalities; DNA Primers; Dose-Response Relationship, Drug; Embryo, Nonmammalian; Fishes; In Situ Hybridization; Molecular Sequence Data; Proliferating Cell Nuclear Antigen; Protein-Lysine 6-Oxidase; Pyrenes; Real-Time Polymerase Chain Reaction; Sequence Analysis, DNA; SOX9 Transcription Factor; Water Pollutants, Chemical

Although the embryonic expression pattern of ADP ribosylation factor-like 6 interacting protein 1 (Arl6ip1) has been reported, its function in neural crest development is unclear.. We found that knockdown of Arl6ip1 caused defective embryonic neural crest derivatives that were particularly severe in craniofacial cartilages. Expressions of the ectodermal patterning factors msxb, dlx3b, and pax3 were normal, but the expressions of the neural crest specifier genes foxd3, snai1b, and sox10 were greatly reduced. These findings suggest that arl6ip1 is essential for specification of neural crest derivatives, but not neural crest induction. Furthermore, we revealed that the streams of crestin- and sox10-expressing neural crest cells, which migrate ventrally from neural tube into trunk, were disrupted in arl6ip1 morphants. This migration defect was not only in the trunk neural crest, but also in the enteric tract where the vagal-derived neural crest cells failed to populate the enteric nervous system. We found that this migration defect was induced by dampened Shh signaling, which may have resulted from defective cilia. These data further suggested that arl6ip1 is required for neural crest migration. Finally, by double-staining of TUNEL and crestin, we confirmed that the loss of neural crest cells could not be attributed to apoptosis.. Therefore, we concluded that arl6ip1 is required for neural crest migration and sublineage specification.

Topics: Adaptor Proteins, Signal Transducing; Alcian Blue; Animals; Cell Movement; Craniofacial Abnormalities; Fluorescent Antibody Technique; Gene Expression Regulation, Developmental; Gene Knockdown Techniques; Hedgehog Proteins; In Situ Hybridization; In Situ Nick-End Labeling; Nerve Tissue Proteins; Neural Crest; Signal Transduction; Zebrafish; Zebrafish Proteins

Zebrafish craniofacial, skeletal, and tooth development closely resembles that of higher vertebrates. Our goal is to identify viable adult zebrafish mutants that can be used as models for human mineralized craniofacial, dental, and skeletal system disorders. We used a large-scale forward-genetic chemical N-ethyl-nitroso-urea mutagenesis screen to identify 17 early lethal homozygous recessive mutants with defects in craniofacial cartilage elements, and 7 adult homozygous recessive mutants with mineralized tissue phenotypes including craniofacial shape defects, fused sutures, dysmorphic or missing skeletal elements, scoliosis, and neural arch defects. One mutant displayed both an early lethal homozygous phenotype and an adult heterozygous phenotype. These results extend the utility of the zebrafish model beyond the embryo to study human bone and cartilage disorders.

Topics: Alcian Blue; Animals; Anthraquinones; Cartilage; Craniofacial Abnormalities; Disease Models, Animal; Ethylnitrosourea; Genes, Recessive; Mutagenesis; Phenotype; Zebrafish