Cleidocranial dysplasia and novel RUNX2 variants: dental, craniofacial, and osseous manifestations

Cleidocranial dysplasia (CCD) is a skeletal disorder affecting cranial sutures, teeth, and clavicles, and is associated with the RUNX2 mutations. Although numerous patients have been described, a direct genotype–phenotype correlation for RUNX2 has been difficult to establish. Further cases must be studied to understand the clinical and genetic spectra of CCD. Objectives: To characterize detailed phenotypes and identify variants causing CCD in five unrelated patients and their family members. Methodology: Clinical and radiographic examinations were performed. Genetic variants were identified by exome and Sanger sequencing, data were analyzed by bioinformatics tools. Results: Three cases were sporadic and two were familial. Exome sequencing successfully detected the heterozygous pathogenic RUNX2 variants in all affected individuals. Three were novel, comprising a frameshift c.739delA (p.(Ser247Valfs*)) in exon 6 (Patient-1), a nonsense c.901C>T (p.(Gln301*)) in exon 7 (Patient-2 and affected mother), and a nonsense c.1081C>T (p.(Gln361*)) in exon 8 (Patient-3). Two previously reported variants were missense: the c.673C>T (p.(Arg225Trp)) (Patient-4) and c.674G>A (p.(Arg225Gln)) (Patient-5) in exon 5 within the Runt homology domain. Patient-1, Patient-2, and Patient-4 with permanent dentition had thirty, nineteen, and twenty unerupted teeth, respectively; whereas Patient-3 and Patient-5, with deciduous dentition, had normally developed teeth. All patients exhibited typical CCD features, but the following uncommon/unreported phenotypes were observed: left fourth ray brachymetatarsia (Patient-1), normal clavicles (Patient-2 and affected mother), phalangeal malformations (Patient-3), and normal primary dentition (Patient-3, Patient-5). Conclusions: The study shows that exome sequencing is effective to detect mutation across ethnics. The two p.Arg225 variants confirm that the Runt homology domain is vital for RUNX2 function. Here, we report a new CCD feature, unilateral brachymetatarsia, and three novel truncating variants, expanding the phenotypic and genotypic spectra of RUNX2 , as well as show that the CCD patients can have normal deciduous teeth, but must be monitored for permanent teeth anomalies

Human serum enhances the proliferative capacity and immunomodulatory property of MSCs derived from human placenta and umbilical cord

Abstract Background Mesenchymal stromal cells (MSCs) are considered potential candidates that hold great promise in the treatment of immune-related diseases. For therapeutic applications, it is necessary to isolate and expand MSCs with procedures complying with good manufacturing practice (GMP). Recent studies reported the use of human serum (HS) instead of fetal bovine serum (FBS) for the expansion of bone marrow-derived MSCs. Nevertheless, there are only limited data on HS as an alternative to FBS for the isolation and expansion of umbilical (UC-MSCs) and placenta-derived MSCs (PL-MSCs). In this study, we evaluate the effect of HS compared to FBS on the proliferative and immunosuppressive capacities of these MSCs. Methods PL-MSCs and UC-MSCs were isolated and cultured in HS- or FBS-supplemented media. The MSC characteristics, including morphology, immunophenotype, and differentiation ability, were verified. The proliferative and immunosuppressive capacities were also examined. In addition, the proliferative-enhancing factors in both sera were explored using proteomic analysis. Results PL-MSCs and UC-MSCs proliferated faster in HS-supplemented medium than in equivalent levels of FBS-supplemented medium. Adipogenic and osteogenic differentiations occurred at nearly identical levels in HS- and FBS-supplemented media. Interestingly, MSCs cultured in HS-supplemented medium had a similar immunosuppressive effect as MSCs cultured in FBS-supplemented medium. Proteomic analysis revealed that Con-A binding glycoproteins with a molecular weight > 100 kDa in FBS could significantly enhance MSC proliferation. In contrast, the proliferative enhancing factors in HS were found in the Con-A non-binding fraction and WGA binding fraction with a molecular weight > 100 kDa. Conclusions Taken together, our results suggest applications for the use of HS instead of FBS for the isolation and expansion of PL-MSCs and UC-MSCs for cell therapy in the future. Furthermore, this study identifies factors in HS that are responsible for its proliferative and immunosuppressive effects and might thus lead to the establishment of GMPs for the therapeutic use of MSCs

Functional consequences of C-terminal mutations in RUNX2

Abstract Cleidocranial dysplasia (CCD) is a genetic disorder caused by mutations in the RUNX2 gene, affecting bone and teeth development. Previous studies focused on mutations in the RUNX2 RHD domain, with limited investigation of mutations in the C-terminal domain. This study aimed to investigate the functional consequences of C-terminal mutations in RUNX2. Eight mutations were analyzed, and their effects on transactivation activity, protein expression, subcellular localization, and osteogenic potential were studied. Truncating mutations in the PST region and a missense mutation in the NMTS region resulted in increased transactivation activity, while missense mutations in the PST showed activity comparable to the control. Truncating mutations produced truncated proteins, while missense mutations produced normal-sized proteins. Mutant proteins were mislocalized, with six mutant proteins detected in both the nucleus and cytoplasm. CCD patient bone cells exhibited mislocalization of RUNX2, similar to the generated mutant. Mislocalization of RUNX2 and reduced expression of downstream genes were observed in MSCs from a CCD patient with the p.Ser247Valfs*3 mutation, leading to compromised osteogenic potential. This study provides insight into the functional consequences of C-terminal mutations in RUNX2, including reduced expression, mislocalization, and aberrant transactivation of downstream genes, contributing to the compromised osteogenic potential observed in CCD

The Prostacyclin Analog Iloprost Promotes Cementum Formation and Collagen Reattachment of Replanted Molars and Up-regulates Mineralization by Human Periodontal Ligament Cells

Introduction: This study evaluated the use of the prostacyclin analog iloprost as a root surface treatment agent in promoting acellular cementum (AC) formation and collagen reattachment after tooth replantation in vivo. In addition, its effect on human periodontal ligament cell (hPDLC) mineralization was assessed in vitro. Methods: First molars of 8-week-old Wistar rats were extracted. In 1 group, the root surfaces were treated with Hank's balanced salt solution (HBSS), and the other group's root surfaces were treated with 10−6 mol/L iloprost before replantation. At day 30, maxillae were prepared for micro–computed tomographic imaging and histomorphometric analysis. The effect of iloprost on mineralization by hPDLCs was analyzed by mineralized nodule formation and quantitative polymerase chain reaction at 7 and 14 days. Results: Micro–computed tomographic imaging demonstrated a significant higher bone volume in the iloprost groups, whereas the HBSS groups had extensive bone and root resorption. Histologic analysis revealed deposition of a thick AC layer along the root in the iloprost group with well-organized periodontal ligament fibers inserted into the cementum. The HBSS group demonstrated more osteoclasts than the iloprost group. In vitro, iloprost-treated hPDLCs had a significantly increased RUNX2, OSX, BSP, and ALP gene expression that coincided with an increased deposition of mineralized nodules. These effects were abrogated by a PGI2 receptor inhibitor. Conclusions: Our results revealed that iloprost promoted PDL regeneration in replanted molars. Furthermore, resorption of the roots was decreased, whereas AC deposition was stimulated. Iloprost-treatment increased hPDLC mineralization and was mediated by PGI2 receptor activation. These observations indicate that iloprost may be a promising root surface treatment agent