Center for Craniofacial Molecular Biology

Los Angeles, CA, United States

Center for Craniofacial Molecular Biology

Los Angeles, CA, United States
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Chen C.,Center for Craniofacial Molecular Biology | Chen C.,University of Pennsylvania | Akiyama K.,Center for Craniofacial Molecular Biology | Akiyama K.,Okayama University of Science | And 9 more authors.
Journal of Experimental Medicine | Year: 2015

Fibrillin-1 (FBN1) deficiency-induced systemic sclerosis is attributed to elevation of interleukin-4 (IL4) and TGF-β, but the mechanism underlying FBN1 deficiency-associated osteopenia is not fully understood. We show that bone marrow mesenchymal stem cells (BMMSCs) from FBN1-deficient (Fbn1+/-) mice exhibit decreased osteogenic differentiation and increased adipogenic differentiation. Mechanistically, this lineage alteration is regulated by IL4/IL4Rα-mediated activation of mTOR signaling to down-regulate RUNX2 and up-regulate PPARγ2, respectively, via P70 ribosomal S6 protein kinase (P70S6K). Additionally, we reveal that activation of TGF-β/SMAD3/SP1 signaling results in enhancement of SP1 binding to the IL4Rα promoter to synergistically activate mTOR pathway in Fbn1+/-BMMSCs. Blockage of mTOR signaling by osteoblastic-specific knockout or rapamycin treatment rescues osteopenia phenotype in Fbn1+/-mice by improving osteogenic differentiation of BMMSCs. Collectively, this study identifies a previously unrecognized role of the FBN1/TGF-β/IL4Rα/mTOR cascade in BMMSC lineage selection and provides experimental evidence that rapamycin treatment may provide an anabolic therapy for osteopenia in Fbn1+/-mice. © 2015 Chen et al.

Jalali R.,VU University Amsterdam | Guo J.,VU University Amsterdam | Zandieh-Doulabi B.,VU University Amsterdam | Bervoets T.J.M.,VU University Amsterdam | And 7 more authors.
Cell and Tissue Research | Year: 2014

During the formation of dental enamel, maturation-stage ameloblasts express ion-transporting transmembrane proteins. The SLC4 family of ion-transporters regulates intra- and extracellular pH in eukaryotic cells by cotransporting HCO3 − with Na+. Mutation in SLC4A4 (coding for the sodium-bicarbonate cotransporter NBCe1) induces developmental defects in human and murine enamel. We have hypothesized that NBCe1 in dental epithelium is engaged in neutralizing protons released during crystal formation in the enamel space. We immunolocalized NBCe1 protein in wild-type dental epithelium and examined the effect of the NBCe1-null mutation on enamel formation in mice. Ameloblasts expressed gene transcripts for NBCe1 isoforms B/D/C/E. In wild-type mice, weak to moderate immunostaining for NBCe1 with antibodies that recognized isoforms A/B/D/E and isoform C was seen in ameloblasts at the secretory stage, with no or low staining in the early maturation stage but moderate to high staining in the late maturation stage. The papillary layer showed the opposite pattern being immunostained prominently at the early maturation stage but with gradually less staining at the mid- and late maturation stages. In NBCe1−/− mice, the ameloblasts were disorganized, the enamel being thin and severely hypomineralized. Enamel organs of CFTR−/− and AE2a,b−/− mice (CFTR and AE2 are believed to be pH regulators in ameloblasts) contained higher levels of NBCe1 protein than wild-type mice. Thus, the expression of NBCe1 in ameloblasts and the papillary layer cell depends on the developmental stage and possibly responds to pH changes. © 2014, Springer-Verlag Berlin Heidelberg.

Costa M.A.,University of Southern California | Borzabadi-Farahani A.,University of Warwick | Borzabadi-Farahani A.,Center for Craniofacial Molecular Biology | Lara-Sanchez P.A.,University of Southern California | And 6 more authors.
Journal of Cranio-Maxillofacial Surgery | Year: 2014

Diprosopus (Greek; di-, "two" + prosopon, "face"), or craniofacial duplication, is a rare craniofacial anomaly referring to the complete duplication of facial structures. Partial craniofacial duplication describes a broad spectrum of congenital anomalies, including duplications of the oral cavity. This paper describes a 15 month-old female with a duplicated oral cavity, mandible, and maxilla. A Tessier type 7 cleft, midline meningocele, and duplicated hypophysis were also present. The preoperative evaluation, surgical approach, postoperative results, and a review of the literature are presented. The surgical approach was designed to preserve facial nerve innervation to the reconstructed cheek and mouth. The duplicated mandible and maxilla were excised and the remaining left maxilla was bone grafted. Soft tissue repair included closure of the Tessier type VII cleft. Craniofacial duplication remains a rare entity that is more common in females. The pathophysiology remains incompletely characterized, but is postulated to be due to duplication of the notochord, as well as duplication of mandibular growth centres. While diprosopus is a severe deformity often associated with anencephaly, patients with partial duplication typically benefit from surgical treatment. Managing craniofacial duplication requires a detailed preoperative evaluation as well as a comprehensive, staged treatment plan. Long-term follow up is needed appropriately to address ongoing craniofacial deformity. © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Iwata J.,Center for Craniofacial Molecular Biology | Suzuki A.,Center for Craniofacial Molecular Biology | Pelikan R.C.,Center for Craniofacial Molecular Biology | Ho T.-V.,Center for Craniofacial Molecular Biology | And 4 more authors.
Human Molecular Genetics | Year: 2014

Mutations in transforming growth factor beta (TGFβ) receptor type II (TGFBR2) cause Loeys-Dietz syndrome, characterized by craniofacial and cardiovascular abnormalities. Mice with a deletion of Tgfbr2 in cranial neural crest cells (Tgfbr2fl/fl;Wnt1-Cre mice) develop cleft palate as the result of abnormal TGFb signaling activation. However, little is known about metabolic processes downstream of TGFβ signaling during palatogenesis. Here, we show that Tgfbr2 mutant palatal mesenchymal cells spontaneously accumulate lipid droplets, resulting from reduced lipolysis activity. Tgfbr2 mutant palatal mesenchymal cells failed to respond to the cell proliferation stimulator sonic hedgehog, derived from the palatal epithelium. Treatment with p38 mitogenactivated protein kinase (MAPK) inhibitor or telmisartan, amodulator of p38 MAPK activation and lipid metabolism, blocked abnormal TGFβ-mediated p38 MAPK activation, restoring lipid metabolism and cell proliferation activity both in vitro and in vivo. Our results highlight the influence of alternative TGFβ signaling on lipid metabolic activities, as well as how lipid metabolic defects can affect cell proliferation and adversely impact palatogenesis. This discovery has broader implications for the understanding of metabolic defects and potential prevention of congenital birth defects. © The Author 2013. Published by Oxford University Press. All rights reserved .

Huang J.M.,Childrens Hospital Los Angeles | Huang J.M.,Center for Craniofacial Molecular Biology | Huang J.M.,Cedars Sinai Medical Center | Sheard M.A.,Childrens Hospital Los Angeles | And 4 more authors.
Molecular Cancer Therapeutics | Year: 2010

As p53 loss of function (LOF) confers high-level drug resistance in neuroblastoma, p53-independent therapies might have superior activity in recurrent neuroblastoma. We tested the activity of vorinostat, a histone deacetylase inhibitor, and flavopiridol, a pan-Cdk inhibitor, in a panel of multidrug-resistant neuroblastoma cell lines that included lines with wild-type (wt) and transcriptionally active TP53 (n = 3), mutated (mt), and LOF TP53 (n = 4) or p14ARF deletion (n = 1). The combination of vorinostat and flavopiridol was synergistic and significantly more cytotoxic (P < 0.001) in cell lines with p53-LOF and in the clones stably transfected with dominant-negative p53 plasmids. Cell cycle analysis by flow cytometry showed prominent cell-cycle arrest in G2/M (37%) for a cell line with wt TP53 (SK-N-RA) at 16 to 20 hours, while cells with mt TP53 (CHLA-90) slipped into sub-G1 at 6 to 24 hours (25%-40% specific cell death). The morphological hallmarks of mitotic cell death, including defective spindle formation and abnormal cytokinesis, were detected by confocal microscopy after the treatment with vorinostat + flavopiridol combination in CHLA-90. The combination caused reduction in the expression of G2/M proteins (cyclin B1, Mad2, MPM2) in 2 cell lines with mt TP53 but not in those with wt TP53. Plk1 expression was reduced in all treated lines. Small interfering RNA knockdown of Mad2 and cyclin B1 or Plk1 synergistically reduced the clonogenicity of CHLA-90 cells. The combination of HDAC inhibitor and flavopiridol may be a unique approach to treating neuroblastomas with p53 LOF, one that evokes induction of mitotic failure. © 2010 AACR.

Feng J.,Center for Craniofacial Molecular Biology | Jing J.,University of Sichuan | Sanchez-Lara P.A.,University of Southern CaliforniaLos Angeles 90033 United States | Bootwalla M.S.,Center for Personalized Medicine | And 4 more authors.
Genesis | Year: 2016

Pax9 encodes a paired-box homeodomain (Pax) transcription factor and is critical for the development of multiple organs. Using CrispR/Cas9-mediated homologous directed repair (HDR), we generated a new Pax9-CreER knock-in mouse line in which the CreERT2 fusion protein is produced after synthesis of endogenous Pax9 protein. We found that tdTomato reporter expression in Pax9-CreER;tdTomato reporter mice is detectable in a similar pattern to the endogenous Pax9 expression, faithfully recapitulating the Pax9 expression domains throughout the embryo and in the adult mouse. At early embryonic stages, the tdTomato reporter is expressed first in the pharyngeal pouch region and later in the craniofacial mesenchyme, somites, limbs, and lingual papillae in the adult tongue. These results demonstrate that this new Pax9-CreER knock-in mouse line can be used for lineage tracing and genetic targeting of Pax9-expressing cells and their progeny in a temporally and spatially controlled manner during development and organogenesis. © 2016 Wiley Periodicals, Inc.

Auyong T.G.,University of Southern California | Le A.,University of Southern California | Le A.,Center for Craniofacial Molecular Biology
Oral and Maxillofacial Surgery Clinics of North America | Year: 2011

Nerve injury associated with dentoalveolar surgery is a complication contributing to the altered sensation of the lower lip, chin, buccal gingivae, and tongue. This surgery-related sensory defect is a morbid postoperative outcome. Several risk factors have been proposed. This article reviews the incidence of trigeminal nerve injury, presurgical risk assessment, classification, and surgical coronectomy versus conventional extraction as an approach to prevent neurosensory damage associated with dentoalveolar surgery. © 2011.

PubMed | Center for Craniofacial Molecular Biology, University of Southern California and Human Genetics
Type: Journal Article | Journal: Human molecular genetics | Year: 2014

Fibroblast growth factor receptor 2 (FGFR2) promotes osteoprogenitor proliferation and differentiation during bone development, yet how the receptor elicits these distinct cellular responses remains unclear. Analysis of the FGFR2-skeletal disorder bent bone dysplasia syndrome (BBDS) demonstrates that FGFR2, in addition to its canonical signaling activities at the plasma membrane, regulates bone formation from within the nucleolus. Previously, we showed that the unique FGFR2 mutations that cause BBDS reduce receptor levels at the plasma membrane and diminish responsiveness to extracellular FGF2. In this study, we find that these mutations, despite reducing canonical signaling, enhance nucleolar occupancy of FGFR2 at the ribosomal DNA (rDNA) promoter. Nucleolar FGFR2 activates rDNA transcription via interactions with FGF2 and UBF1 by de-repressing RUNX2. An increase in the nucleolar activity of FGFR2 in BBDS elevates levels of ribosomal RNA in the developing bone, consequently promoting osteoprogenitor cell proliferation and decreasing differentiation. Identifying FGFR2 as a transcriptional regulator of rDNA in bone unexpectedly reveals a nucleolar route for FGF signaling that allows for independent regulation of osteoprogenitor cell proliferation and differentiation.

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