Project description:Mesenchymal stem cells (MSCs) are multipotent progenitor cells present in various mesenchymal tissues that undergo strict lineage-specific differentiation programs, faithful to their unique tissue origins. However, the key regulators that activate dental pulp MSC commitment to odontogenesis remain unclear. In this study, we utilized an inducible Cre/loxP system to interrupt BMP signaling in apical MSCs at the onset of molar root formation in order to investigate the functional requirement for BMP signaling and its downstream targets in MSC cell fate determination during tooth morphogenesis.
Project description:BMP (bone morphogenetic protein) signaling plays essential roles in the regulation of early tooth development. It is well acknowledged that with binding of extracellular BMP ligands to the type I and type II transmembrane serine/threonine kinase receptor complexes when triggering of the BMP canonical signaling pathway, receptor activated Smad1/5/8 in cytoplasm bind to Smad4, the central mediator of the canonical BMP signaling pathway, to form transfer complexes for entering the nucleus and regulating target gene expression. However, our recent studies reveal the functional operation of a novel BMP mediated signaling pathway named as the atypical BMP canonical signaling pathway in mouse developing tooth, which is Smad1/5/8 dependent but Smad4 independent. In the current study, we investigated whether this atypical BMP canonical signaling is conserved in human odontogenesis. We showed that pSmad1/5/8 is required for expression of MSX1, a well-defined BMP signaling target gene, in human dental mesenchyme, but the typical BMP canonical signaling is indeed not operating in the early human developing tooth, as assessed by the absence of pSMAD1/5/8-SMAD4 complexes in the dental mesenchyme and expression of MSX1 and translocation of pSMAD1/5/8 induced by BMP4 protein is SMAD4-independent in dental mesenchymal cells. Moreover, RNA-Seq data sets comparing the transcriptome profiles of human dental mesenchymal cells with and without SMAD4 knockdown by siRNA displays unchanged expression profiles of pSMAD1/5/8 downstream target genes, further affirming the functional operation of the atypical canonical BMP signaling pathway in a manner of SMAD1/5/8-dependent but SMAD4-independent in the dental mesenchyme during early odontogenesis.
Project description:Taste papillae are specialized organs, each of which comprises an epithelial wall hosting taste buds and a core of mesenchymal tissue. In the present study, we report that during early taste papilla development in mouse embryos, bone morphogenetic protein (BMP) signaling mediated by type 1 receptor ALK3 in the tongue mesenchyme is required for the epithelial Wnt/β-catenin activity and taste papilla differentiation.
Project description:Iron induces hepcidin by activating bone morphogenetic protein (BMP)6-SMAD signaling, which is critical for regulation of systemic iron homeostasis. High iron levels induce BMP6 production in liver endothelial cells, but the molecular mechanisms by which iron regulates BMP6 are incompletely understood. To address this, we performed RNA-sequencing on sorted liver endothelial cells from iron-adequate and iron-loaded mice.
Project description:Dental mesenchymal cells (dMCs) differentiate into dentin-secreting odontoblasts and are utilized in the majority of tooth regeneration studies to produce an entire tooth organ. An in vitro culture platform of dMCs is useful in generating an adequate quantity of cells for experiments and regenerative therapy. However, culturing techniques may induce functional modification in dMCs. Here, we examined the transcriptomic alterations induced by in vitro culture and investigated the biological properties of cultured dMCs. Hierarchical clustering analysis and principal components analysis reveal an overall transcriptional similarity between the first and second passages that differed significantly from freshly obtained cells. Following in vitro culture, the biological processes of cell adhesion, chromatin organization, cell differentiation and development are significantly altered. Components of signaling pathways, including p53, transforming group factor β/bone morphogenetic protein (TGFβ/BMP), Hedgehog, and Wnt, as well epigenetic regulators are involved. Furthermore, the osteogenic potential of cultured dMCs is also impaired. Our study provides valuable insights for the modification of the current culturing methods to maintain the characteristics of in vivo dMCs.
Project description:In orthodontic therapy periodontal tissue responds to mechanical stimuli by bone remodeling mediated by specific molecules involved in periodontal regeneration and homeostasis. The resulting changes are reflected in the salivary proteome that is emerging as a valuable diagnostic tool. We analyzed the changes of saliva proteome during orthodontic tooth movement in 12 healthy male patients, presented with malocclusion treated by placement of fixed orthodontic appliance. Six patients with identical dental pathology, but no orthodontic therapy were used as control samples. Saliva was collected a day before, immediately after, and 2, 7 and 30 days after the placement of the fixed orthodontic appliance and analyzed by LC-MS. Total of 198 proteins were identified and classified on the basis of their functional characteristics. Proteins involved in bone remodeling, inflammation and healing were detected mostly 30 days after placement of the fixed orthodontic appliance. At this time point, Bone morphogenetic protein 4 emerged as a central player in the ongoing dental bone remodeling. Besides BMP4, BMP antagonists: BMP Binding Endothelial Regulator (BMPER), Insulin-like growth factor-binding protein 3 (IGFBP3), Cytoskeleton-associated protein 4 (CKAP4) and Fibroblast growth factor 5 (FGF5), were also identified. Presence of BMP4 in human saliva 30 days after the placement of orthodontic fixed appliance was confirmed by ELISA and concentration of BMP4 was 3.2 pg/ml. To date, there is no published data on the presence of BMP molecules or their antagonists in saliva or the gingival cervical fluid, regardless of different orthodontic treatments or disease. BMP4 is involved not only in orthodontic treatment, but also in processes involving tooth development and homeostasis. Therefore, a better understanding of its networks in bone remodeling during OTM is heralded.
Project description:Bone morphogenetic proteins (BMPs) regulate many aspects of skeletal development, including osteoblast and chondrocyte differentiation, cartilage and bone formation, and cranial and limb development. Among them, BMP2, one of the most potent osteogenic signaling molecules, stimulates osteoblast differentiation. We used cDNA microarrays to elucidate regulators of BMP-2-induced osteoblast differentiation.
Project description:Bone marrow-derived mesenchymal stem cells (MSCs) differentiate into osteoblasts upon induction by signals present in their niche. As the global signaling cascades involved in the early phases of MSCs osteoblast (OB) differentiation are not well-defined, we employed quantitative mass spectrometry (SILAC based) to delineate changes in human MSCs proteome and phosphoproteome during the first 24 hours of their OB lineage commitment. The temporal profiles of 6,252 proteins and 15,059 phosphorylation sites suggested at least two distinct signaling waves: one peaking within 30 to 60 min after induction and a second upsurge after 24 hours
Project description:Implantation of an embryo in the uterus is a multistep process tightly controlled by an intricate regulatory network of interconnected ovarian, uterine, and embryonic factors. Bone morphogenetic protein (BMP) ligands and receptors are expressed in the pregnant uterus, and BMP2 has been shown to be a key regulator of implantation. In this study, we investigated the roles of the BMP type 1 receptor, activin-like kinase 2 (ALK2), during mouse pregnancy by producing uterine-specific Alk2 conditional knockout (cKO) mice. In the absence of ALK2, embryos can invade the uterine epithelium and stroma, but stromal cells cannot undergo uterine decidualization, resulting in sterility. Mechanistically, microarray analysis revealed that CCAAT/enhancer-binding protein β (Cebpb) expression is suppressed during decidualization in Alk2 cKO females. These findings and the similar phenotypes of Cebpb cKO and Alk2 cKO mice lead to the hypothesis that BMPs act upstream of C/EBPβ to regulate decidualization. To test this hypothesis, we knocked down ALK2 in human uterine stromal cells (HESC) and discovered that ablation of ALK2 alters HESC decidualization and suppresses CEBPB mRNA and protein levels. Chromatin immunoprecipitation (ChIP) analysis of decidualizing HESC confirmed that BMP signaling protein, SMAD1, directly regulates expression of CEBPB by binding a distinct regulatory sequence in the CEBPB promoter; C/EBPβ, in turn, regulates the expression of progesterone receptor (PGR). Our work clarifies the conserved mechanisms through which BMPs regulate embryo implantation in rodents and primates and, for the first time, uncovers a linear pathwayof BMP signaling through ALK2 to regulate CEBPB and, subsequently, PGR during decidualization. gene expression profiling of two groups: control mice and Alk2 cKO mice
Project description:Bone morphogenetic proteins (BMPs) regulate many aspects of skeletal development, including osteoblast and chondrocyte differentiation, cartilage and bone formation, and cranial and limb development. Among them, BMP2, one of the most potent osteogenic signaling molecules, stimulates osteoblast differentiation, while it inhibits myogenic differentiation in C2C12 cells. We used cDNA microarrays to elucidate regulators of BMP-2-induced osteoblast differentiation.