Research progress on the regulation of craniofacial development and malformation by fibroblast growth factor 8 / 口腔疾病防治

@#Fibroblast growth factor 8 (FGF8) is a kind of secretory polypeptide that has crucial roles in the development of various tissues and organs. Current studies have found that FGF8 can regulate the differentiation of cranial neural crest cells by activating the mitogen-activated protein kinase (MAPK) signaling pathway and affect the establishment of mandibular arch polarity and the development of craniofacial symmetry by regulating the expression of target genes. Cleft lip with or without cleft palate, ciliopathies, macrostomia and agnathia are four developmental malformations involving the craniofacial region that seriously affect the quality of life of patients. The abnormal FGF8 signal caused by gene mutation, abnormal protein conformation or expression is closely related to the occurrence of craniofacial malformations, but the molecular mechanism and signaling pathway underlying these malformations have not been fully elucidated. Craniofacial development is a complex process mediated by a variety of signaling molecules. In the future, the role of various signaling molecules in craniofacial development and malformations need to be explored to provide a new perspective and vision for the prevention and treatment of these craniofacial malformations.

Does Dlx abnormal expression regulate the migration of cranial neural crest cells and development of the first brachial arch? / 中国组织工程研究

BACKGROUND: Dlx gene family is highly expressed in the cranial neural crest cells, and regulates the cranial neural crest cel migration and differentiation. OBJECTIVE: To review the mechanism that the highly-expressed Dlx genes mediate the cranial neural crest cel migration and differentiation. METHODS: An online search of CNKI and Medline databases was performed for articles published before 2013 using keywords of “cranial neural crest cells, migration of cranial neural crest cells, Dlx, Dlx overexpression, Fgf, chodrogenesis, osteogenesis” in Chinese and English, respectively. Relevant articles were summarized from three aspects: the migration of cranial neural crest cells, Dlx over-expression’s impact on the migration of cranial neural crest cells, interaction between the environment and Dlx genes. A total of 63 articles were included. According to inclusion criteria, 43 articles were retained at last. RESULTS AND CONCLUSION: Dlx abnormal-expression wil lead to cel -cel adhesion. Dlx over-expression wil induce most of the cranial neural crest cells aggregate and migrate to a wrong place, and result in skeletal dysmorphology. Dlx over-expression wil also lead to ectopic chondrogenesis, and the interaction between cel factors can be the possible reason for this.

Conditional deletion of the human ortholog gene Dicer1 in Pax2-Cre expression domain impairs orofacial development.

Background: Orofacial clefts are common worldwide and result from insufficient growth and/or fusion during the genesis of the derivatives of the first pharyngeal arch and the frontonasal prominence. Recent studies in mice carrying conditional and tissue-specific deletions of the human ortholog Dicer1, an RNAse III family member, have highlighted its importance in cell survival, differentiation, proliferation, and morphogenesis. Nevertheless, information regarding Dicer1 and its dependent microRNAs (miRNAs) in mammalian palatogenesis and orofacial development is limited. Aims: To describe the craniofacial phenotype, gain insight into potential mechanisms underlying the orofacial defects in the Pax2-Cre/Dicer1 CKO mouse, and shed light on the role of Dicer1 in mammalian palatogenesis. Materials And Methods: Histological and molecular assays of wild type (WT) and Pax2-Cre/Dicer1 loxP/loxP (Dicer1 CKO) mice dissected tissues have been performed to characterize and analyze the orofacial dysmorphism in Pax2-Cre/Dicer1 loxP/loxP mouse. Results: Dicer1 CKO mice exhibit late embryonic lethality and severe craniofacial dysmorphism, including a secondary palatal cleft. Further analysis suggest that Dicer1 deletion neither impacts primary palatal development nor the initial stages of secondary palatal formation. Instead, Dicer1 is implicated in growth, differentiation, mineralization, and survival of cells in the lateral palatal shelves. Histological and molecular analysis demonstrates that secondary palatal development becomes morphologically arrested prior to mineralization around E13.5 with a significant increase in the expression levels of apoptotic markers (P < 0.01). Conclusions: Pax2-Cre-mediated Dicer1 deletion disrupts lateral palatal outgrowth and bone mineralization during palatal shelf development, therefore providing a mammalian model for investigating the role of miRNA-mediated signaling pathways during palatogenesis.