Genetic association studies of cleft lip and/or palate with hypodontia outside the cleft region
CLEFT PALATE-CRANIOFACIAL JOURNAL
Authors: Slayton, RL; Williams, L; Murray, JC; Wheeler, JJ; Lidral, AC; Nishimura, CJ
Abstract
Objective: The purpose of this study was to determine whether the candidate genes previously studied in subjects with cleft lip, cleft palate, or both are associated with hypodontia outside the region of the cleft. Subjects: One hundred twenty subjects from the Iowa Craniofacial Anomalies Research Center were selected based on the availability of both dental records and genotype information. Method: The type of orofacial clefting and type and location of dental anomalies (missing teeth, supernumerary teeth, or peg laterals) were assessed by dental chart review and radiographic examination. Genotype analysis of candidate genes was performed using polymerase chain reaction/single-strand conformation polymorphism analysis. Results: The prevalence of hypodontia in this sample was 47.5%, with 30.0% of subjects having missing teeth outside the cleft. There was a positive association between subjects with cleft lip or cleft lip and palate who had hypodontia outside the cleft region (compared with noncleft controls) and both muscle segment homeo box homolog 1 (MSX1) (p=.029) and transforming growth factor beta 3 (TGFB3) (p=.024). It was not possible in this analysis to determine whether this association was specifically associated with orofacial clefting combined with hypodontia or whether it was due primarily to the clefting phenotype. Conclusions: In this sample, there was a significantly greater incidence of hypodontia outside the cleft region in subjects with cleft lip and palate, compared with cleft lip only or cleft palate only. Cleft lip and/or palate with hypodontia outside the cleft region was positively associated with both TGFB3 and MSX1, compared with noncleft controls.
Osteogenic Stimulation of Human Adipose-Derived Mesenchymal Stem Cells Using a Fungal Metabolite That Suppresses the Polycomb Group Protein EZH2
STEM CELLS TRANSLATIONAL MEDICINE
Authors: Samsonraj, Rebekah M.; Dudakovic, Amel; Manzar, Bushra; Sen, Buer; Dietz, Allan B.; Cool, Simon M.; Rubin, Janet; van Wijnen, Andre J.
Abstract
Strategies for musculoskeletal tissue regeneration apply adult mesenchymal stem/stromal cells (MSCs) that can be sourced from bone marrow- and lipo-aspirates. Adipose tissue-derived MSCs are more easily harvested in the large quantities required for skeletal tissue-engineering approaches, but are generally considered to be less osteogenic than bone marrow MSCs. Therefore, we tested a new molecular strategy to improve their osteogenic lineage-differentiation potential using the fungal metabolite cytochalasin D (CytoD). We show that CytoD, which may function by redistributing the intracellular location of beta-actin (ACTB), is a potent osteogenic stimulant as reflected by significant increases in alkaline phosphatase activity, extracellular matrix mineralization, and osteoblast-related gene expression (e.g., RUNX2, ALPL, SPARC, and TGFB3). RNA sequencing analyses of MSCs revealed that acute CytoD treatment (24 hours) stimulates a broad program of osteogenic biomarkers and epigenetic regulators. CytoD decreases mRNA and protein levels of the Polycomb chromatin regulator Enhancer of Zeste Homolog 2 (EZH2), which controls heterochromatin formation by mediating trimethylation of histone 3 lysine 27 (H3K27me3). Reduced EZH2 expression decreases cellular H3K27me3 marks indicating a global reduction in heterochromatin. We conclude that CytoD is an effective osteogenic stimulant that mechanistically functions by blocking both cytoplasmic actin polymerization and gene-suppressive epigenetic mechanisms required for the acquisition of the osteogenic phenotype in adipose tissue-derived MSCs. This finding supports the use of CytoD in advancing the osteogenic potential of MSCs in skeletal regenerative strategies.