Animals ; Bone Morphogenetic Protein Receptors ; Bone Morphogenetic Proteins ; genetics ; physiology ; Cell Differentiation ; Gene Expression Regulation ; Hair Follicle ; cytology ; embryology ; physiology ; Humans ; Receptors, Growth Factor ; analysis ; Stem Cells ; cytology

Bone morphogenetic proteins (BMPs) are the largest subfamily of the transforming growth factor-β superfamily, and they play important roles in the development of numerous organs, including the inner ear. The inner ear is a relatively small organ but has a highly complex structure and is involved in both hearing and balance. Here, we discuss BMPs and BMP signaling pathways and then focus on the role of BMP signal pathway regulation in the development of the inner ear and the implications this has for the treatment of human hearing loss and balance dysfunction.
Body Patterning ; Bone Morphogenetic Protein Receptors/physiology* ; Bone Morphogenetic Proteins/physiology* ; Cell Differentiation ; Cochlea/embryology* ; Ear, Inner/embryology* ; Hedgehog Proteins/physiology* ; Humans ; Signal Transduction/physiology* ; Smad Proteins/physiology* ; Vestibule, Labyrinth/embryology* ; Wnt Signaling Pathway

OBJECTIVETo study the role of antenatal glucocorticoid (dexamethasone and betamethasone) on bone morphogenetic protein (BMP) signal transduction of the rat fetal lungs.

METHODSFifteen pregnant rats were randomly divided into five groups: the rats treated with dexamethasone for 1 day (1D-DEX) or 3 days (3D-DEX), with betamethasone for 1 day (1D-BEX) or 3 days (3D-BEX) or with normal saline (control group), followed cesarean section on the 19th day of gestation. The mRNA levels of BMP4, BMPR-II, Smad1 and ATF-2 of fetal rat lungs were ascertained by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of BMP4, BMPR-II, Smad1 and ATF-2 antigen expression in fetal lungs was assessed by immune histochemical staining. The expression of BMP4 and BMPR-II was determined by Western blot.

RESULTSThe levels of BMP4, BMPR-II and Smad1 mRNA expression were up-regulated in the 1D-BEX, 3D-BEX and 3D-DEX groups compared with those in the control group (P<0.05). The immune histochemiscal analysis showed that the expression of BMP4, BMPR-II, Phospho-Smad1 (pSmad1) and ATF-2 in the 1D-BEX, 3D-BEX and 3D-DEX groups was significantly higher than that in the control group (P<0.01). The results of Western blot demonstrated that the expression of BMP4 and BMPR-II protein increased significantly in the 1D-BEX, 3D-BEX and 3D-DEX groups when compared with the control group (P<0.01).

CONCLUSIONSBetamethasone and dexamethasone may play important roles in the regulation of BMP signal transduction in the rat fetal lungs. Up-regulation of BMP4, BMPR-II and Smad1 might be one of crucial factors for the glucocorticoid-induced maturity of fetal lungs.

Activating Transcription Factor 2 ; analysis ; genetics ; Animals ; Betamethasone ; pharmacology ; Bone Morphogenetic Protein 4 ; analysis ; genetics ; physiology ; Bone Morphogenetic Protein Receptors, Type II ; analysis ; genetics ; Dexamethasone ; pharmacology ; Female ; Fetus ; drug effects ; metabolism ; Lung ; drug effects ; metabolism ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Smad1 Protein ; analysis ; genetics

OBJECTIVETo study the roles of the Notch2-Delta signaling in the differentiation of dental pulp cells into odontoblasts in vitro.

METHODSA long-term culture system was used as a model for the study of proliferation and differentiation of pulp cells into preodontoblasts. The expression patterns of Notch2 and its ligand Delta in different phases of long-term cultured dental pulp cells were studied by immunohistochemistry and western blotting. Furthermore, the effects of rhBMP-2 on the expression of Notch signaling members were studied.

RESULTSNotch2 and its ligand Delta expressed in all phases of dental pulp cells and the sites and levels of their expression changed with different phases. rhBMP-2 could significantly up-regulated the expression of Delta in the phase of later cell nodule formation.

CONCLUSIONThis study demonstrated that Notch signaling pathway played roles in the differentiation of long-term cultured human dental pulp cells which formed nudules that were slightly mineralized and had ultrastructural features reminiscient of preodontoblasts, and it may be the mechanism that control pulpal cell's responsiveness to signaling molecules in the healing of wound pulp.

Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; pharmacology ; Cell Differentiation ; Cells, Cultured ; Dental Pulp ; cytology ; metabolism ; Humans ; Immunohistochemistry ; Intracellular Signaling Peptides and Proteins ; Membrane Proteins ; biosynthesis ; physiology ; Odontoblasts ; cytology ; metabolism ; Receptor, Notch2 ; Receptors, Cell Surface ; biosynthesis ; physiology ; Recombinant Proteins ; pharmacology ; Signal Transduction ; Transforming Growth Factor beta

OBJECTIVEConventional deletion of ALK3, also termed as bone morphogenetic protein (BMP) receptor IA, in mice might result in early embryonic lethality. To investigate the function of ALK3 in cardiac development, the cardiac-specific deletion of ALK3 in mice was made by Dr. Schneider, using Cre recombinase driven by the alpha-MHC promoter that Dr. Fukushipe worked out. Such specific deletion of ALK3 caused death in mid-gestation with defects in the trabeculae, interventricular septum, and endocardial cushion. Since ALK3 is not a cardiac-specific gene, it is extremely important to identify ALK3 downstream genes.

METHODSAlpha-MHC Cre+/-, ALK3 F/- and alpha-MHC Cre+/-, ALK3 F/+ embryos were obtained after 20 alpha-MHC Cre+/-, ALK3 +/- mice and 20 ALK3 F/F mice were mating. The ALK3 downstream genes were screened using microarray made in Germany that could identify 25000 genes in mouse. Two populations of mRNA, one derived from the embryonic heart (11.5 days) of alpha-MHC Cre+/-, ALK3 F/- mice, and the other derived from the alpha-MHC Cre+/-, ALK3 F/+ mice, were compared. Cardiac-specific ALK3 downstream genes were identified using real time quantitative RT-PCR and in situ hybridization.

RESULTSThe expression of 12 genes, such as Pax-8 and Hox-3.5 were down-regulated in alpha-MHC Cre+/-, ALK3 F/- mouse heart. The expression of 16 genes including Ras-related protein Rab-5b and EPS-8 protein was up-regulated in the group of alpha-MHC Cre+/-, ALK3 F/-. It was found that the Box protein Pax-8 gene was down-regulated by 7.1 fold (P < 0.001) in the alpha-MHC Cre+/-, ALK3 F/- mice by real time quantitative RT-PCR. It was also revealed that the Box protein Pax-8 gene was expressed stronger in alpha-MHC Cre+/-, ALK3 F/+ than alpha-MHC Cre+/-, ALK3 F/- E11.5 days mouse heart by means of in situ hybridization.

CONCLUSIONThe Box protein Pax-8 gene is an important and cardiac-specific ALK3 downstream gene in the BMP signaling pathway during inter-ventricular septum development.

Animals ; Bone Morphogenetic Protein Receptors ; DNA-Binding Proteins ; genetics ; Down-Regulation ; Female ; Heart ; embryology ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Myocardium ; metabolism ; pathology ; Nuclear Proteins ; Oligonucleotide Array Sequence Analysis ; PAX8 Transcription Factor ; Paired Box Transcription Factors ; Receptors, Growth Factor ; genetics ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; Trans-Activators ; genetics

To investigate the function of ALK3 gene, the gene regulation and the signaling pathway related to ventricular septum defect during heart development. The model mice with ALK3 gene knock-out via alpha-MHC-Cre/lox P system were bred. The mRNA expression level of control group was compared with that of experiment group and ALK3 downstream genes were screened using PCR-select cDNA subtraction microarray. The mRNA of control group was extracted from E11.5 normal mouse hearts, and that of experiment group, from E11.5 hearts of mice with alpha-MHC Cre(+/-) ALK3(F/+) genotype. It was found that the mice with ALK3 gene knock-out produced heart defects involving the interventricular septum. The platelet-activating factors acetylhydrolase and the transcription factor Pax-8 and so on, were down-regulated. However, the Protein Tyrosine Kinase (PTK) of Focal Adhesion Kinase (FAK) subfamily and beta subtype protein 14-3-3 were up-regulated in the alpha-MHC Cre(+/-) ALK3(F/-) mice. These data provide support that ALK3 gene played an important role during heart development. The platelet-activating factors acetylhydrolase and Pax-8 genes could be important ALK3 downstream genes in the BMP signaling pathway during interventricular septum development. PTK and beta subtype protein 14-3-3 might be regulatory factors in this pathway.
1-Alkyl-2-acetylglycerophosphocholine Esterase ; genetics ; metabolism ; 14-3-3 Proteins ; genetics ; metabolism ; Animals ; Bone Morphogenetic Protein Receptors, Type I ; genetics ; metabolism ; Genotype ; Heart Septal Defects, Ventricular ; genetics ; Mice ; Mice, Knockout ; Oligonucleotide Array Sequence Analysis ; PAX8 Transcription Factor ; Paired Box Transcription Factors ; genetics ; metabolism ; Protein-Tyrosine Kinases ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; genetics ; physiology