Proangiogenic effect and underlying mechanism of holmium oxide nanoparticles: a new biomaterial for tissue engineering.

BACKGROUND: Early angiogenesis provides nutrient supply for bone tissue repair, and insufficient angiogenesis will lead tissue engineering failure. Lanthanide metal nanoparticles (LM NPs) are the preferred materials for tissue engineering and can effectively promote angiogenesis. Holmium oxide nanoparticles (HNPs) are LM NPs with the function of bone tissue "tracking" labelling. Preliminary studies have shown that HNPs has potential of promote angiogenesis, but the specific role and mechanism remain unclear. This limits the biological application of HNPs. RESULTS: In this study, we confirmed that HNPs promoted early vessel formation, especially that of H-type vessels in vivo, thereby accelerating bone tissue repair. Moreover, HNPs promoted angiogenesis by increasing cell migration, which was mediated by filopodia extension in vitro. At the molecular level, HNPs interact with the membrane protein EphrinB2 in human umbilical vein endothelial cells (HUVECs), and phosphorylated EphrinB2 can bind and activate VAV2, which is an activator of the filopodia regulatory protein CDC42. When these three molecules were inhibited separately, angiogenesis was reduced. CONCLUSION: Overall, our study confirmed that HNPs increased cell migration to promote angiogenesis for the first time, which is beneficial for bone repair. The EphrinB2/VAV2/CDC42 signalling pathway regulates cell migration, which is an important target of angiogenesis. Thus, HNPs are a new candidate biomaterial for tissue engineering, providing new insights into their biological application.

Promotion effect of apical tooth germ cell-conditioned medium on osteoblastic differentiation of periodontal ligament stem cells through regulating miR-146a-5p.

BACKGROUND: MicroRNAs (miRNAs) play an important role in gene regulation that controls stem cells differentiation. Periodontal ligament stem cells (PDLSCs) could differentiate into osteo-/cementoblast-like cells that secretes cementum-like matrix both in vitro and in vivo. Whether miRNAs play key roles in osteoblastic differentiation of PDLSCs triggered by a special microenviroment remains elusive. In this study, we aimed to investigate potential miRNA expression changes in osteoblastic differentiation of PDLSCs by the induction of apical tooth germ cell-conditioned medium (APTG-CM). METHODS AND RESULTS: First, we analyzed the ability of APTG-CM to osteogenically differentiate PDLSCs. The results exhibited an enhanced mineralization ability, higher ALP activity and increased expression of osteogenic genes in APTG-CM-induced PDLSCs. Second, we used miRNA sequencing to analyze the miRNA expression profile of PDLSCs derived from three donors under 21-day induction or non-induction of APTG-CM. MiR-146a-5p was found to be up-regulated miRNA in induced PDLSCs and validated by RT-qPCR. Third, we used lentivirus-up/down system to verify the role of miR-146a-5p in the regulation of osteoblastic differentiation of PDLSCs. CONCLUSIONS: In conclusion, our results demonstrated that miR-146a-5p was involved in the promotion effect of APTG-CM on osteoblastic differentiation of PDLSCs, and suggested that miR-146a-5p might be a novel way in deciding the direction of PDLSCs differentiation.

Potential susceptibility genes in patients with stage III and IV periodontitis: A whole-exome sequencing pilot study.

The aim of this study was to screen potential susceptibility genes using whole-exome sequencing (WES) in 15 Han Chinese patients with stage III or IV periodontitis and to evaluate the quantity and quality of genomic DNA extracted from saliva. DNA was extracted from saliva epithelial cells, quality-tested, and then subjected to WES and bioinformatics analyses. All variation loci were analyzed and interpreted following the American College of Medical Genetics and Genomics (ACMG) criteria. Candidate pathogenic variation loci were identified and verified using Sanger sequencing. Correlation and functional analyses of the candidate genes were used to identify potential susceptibility genes in patients with severe periodontitis. LFNG, LENG8, NPHS1, HFE, ILDR1, and DMXL2 genes were identified in over two cases each with shared mutations. Following these analyses, the DMXL2 gene was identified as being associated with stage III and IV periodontitis. These results suggest a potential pathophysiological risk mechanism for periodontitis, but need to be verified through larger clinical studies and mechanistic experiments to determine the pathogenicity of these gene mutations and their generalizability to a wider population of periodontitis patients. By screening candidate pathogenic variation loci using WES in 15 Han Chinese patients with stage III or IV periodontitis, our study could provide a pipeline and feasibility support for the identification of susceptibility genes in patients with stage III and IV periodontitis.

The expression of two collagen receptor subfamilies, integrins and discoidin domains during osteogenic and chondrogenic differentiation of human mesenehymal stem cells.

BACKGROUND: Collagen receptors are characterized by binding to and being activated by collagens. We know little about the molecular mechanism by which the integrins and discoidin domains (DDRs) recognize collagen. OBJECTIVE: The aim of this study was to investigate the expression of two main collagen receptor subfamilies, integrins and DDRs, during osteogenic and chondrogenic differentiation of human mesenehymal stem cells (hMSCs). METHODS: Using qRT-PCR, Western blots and FACS, the levels of DDR1, DDR2, integrin subunits ß1, α1, α2, α10 and α11 receptors on hMSCs, were assessed upon activation by collagen type I, as well as during osteogenic and chondrogenic differentiation. RESULTS: The expression of DDR2 and integrin α11ß1 was altered compared with other receptors when the cells were cultured under undifferentiated conditions. During osteogenic and chondrogenetic differentiation, DDR2 and α11 were up-regulated during early stages (6 day) of osteogenesis and chondrogenesis, respectively. The expression and activation of DDR2 was concomitant with another receptor integrin subunit ß1 during osteogenetic differentiation. CONCLUSIONS: The results suggested that DDR2 was more specific for osteogenesis than chondrogenesis, while integrin α11ß1 was more specific in chondrogenesis. DDR2 and α11 may play a role in the regulation of osteogenesis and chondrogenesis based on the differential expression of these receptors during lineage-dependent changes.

The effect of modifying the nanostructure of gelatin fiber scaffolds on early angiogenesisin vitroandin vivo.

Early angiogenesis is one of the key challenges in tissue regeneration. Crosslinking mode and fiber diameter are critical factors to affect the adhesion and proliferation of cells. However, whether and how these two factors affect early angiogenesis remain largely unknown. To address the issue, the optimal crosslinking mode and fiber diameter of gelatin fiber membrane for early angiogenesisin vivoandin vitrowere explored in this work. Compared with the post crosslinked gelatin fiber membrane with the same fiber diameter, the 700 nm diameterin situcrosslinked gelatin fiber membrane was found to have smaller roughness (230.67 ± 19 nm) and stronger hydrophilicity (54.77° ± 1.2°), which were suitable for cell growth and adhesion. Moreover, thein situcrosslinked gelatin fiber membrane with a fiber diameter of 1000 nm had significant advantages in early angiogenesis over the two with fiber diameters of 500 and 700 nm by up-regulating the expression of Ang1, VEGF, and integrin-ß1. Our findings indicated that thein situcrosslinked gelatin fiber membrane with a diameter of 1000 nm might solve the problem of insufficient blood supply in the early stage of soft tissue regeneration and has broad clinical application prospects in promoting tissue regeneration.

miR­10a­5p inhibits osteogenic differentiation of bone marrow­derived mesenchymal stem cells.

The use of human bone marrow mesenchymal stem cells (hBMSCs) as a tissue engineering application for individuals affected by osteoporosis and other types of bone loss diseases has been well studied in recent years. The osteogenic differentiation of hBMSCs can be regulated by a number of cues. MicroRNAs (miRNAs/miRs) serve as the key regulators of various biological processes; however, to the best of our knowledge, no information exists with regards to the specific modulatory effects of miR­10a­5p on osteogenic differentiation of hBMSCs. The aim of the present study was to investigate the relationship between hBMSCs and miR­10a­5p and, ultimately, to determine how miR­10a­5p affects the osteogenic differentiation process of hBMSCs in vitro and in vivo. The hBMSCs used in the present study were transfected with mirVana™ miRNA inhibitors and mimics, and transfection efficiency was assessed by fluorescence microscopy and reverse transcription­quantitative PCR (RT­qPCR). Viability of hBMSCs following transfection was analyzed using a Cell Counting Kit­8 assay. The mRNA expression levels of specific osteoblast markers, including alkaline phosphatase (ALP) and runt­related transcription factor 2 (RUNX2) were measured using RT­qPCR and western blot analysis. New bone formation was evaluated by Goldner's trichrome staining and micro­CT analysis in vivo. No significant difference in cell viability was observed among the different groups 24 h post­transfection. Overexpression of miR­10a­5p inhibited the expression of osteoblast makers in hBMSCs, whereas inhibition of miR­10a­5p upregulated the expression of ALP and RUNX2 in vitro. Furthermore, miR­10a­5p acted as a suppressor during the process of new bone formation in vivo. In conclusion, the findings of the present study suggested that miR­10a­5p served as a negative regulatory factor during osteoblast differentiation of hBMSCs and may be utilized in a treatment approach for bone repair in osteogenic­related diseases.

Abnormal expression of long noncoding RNA FGD5-AS1 affects the development of periodontitis through regulating miR-142-3p/SOCS6/NF-κB pathway.

Periodontitis refers to the inflammation of gums and the surrounding structures and caused by a bacterial infection. The infection occurs owing to poor oral hygiene and could destroy the bone and the gum over time if left untreated. The present study identified the involvement of a key long noncoding RNA (lncRNA), i.e. FGD5-AS1, in the pathogenesis of periodontitis by assessing its expression in the gingival tissues of patients diagnosed with chronic periodontitis (CP). Overexpression of FGD5-AS1 in primary human periodontal ligament cells (PDLCs) significantly reduced the lipopolysaccharide (LPS)-induced periodontitis, whereas its suppression aggravated this injury. Moreover, the miR-142-3p was markedly expressed in the gingival samples of patients diagnosed with CP and LPS-induced PDLCs. We found that the FGD5-AS1-mediated reduction in the inflammation was mediated through downside regulation of miR-142-3p, as evident from the upregulation of SOCS6, a target gene of miR-142-3p. Furthermore, the association between FGD5-AS1 and NF-κB pathway was detected. FGD5-AS1 was found to protect against LPS-stimulated PDLC injury through restraining the NF-κB signals. Based on these findings, we conclude that up-regulation of lncRNA FGD5-AS1 could protect against periodontitis via regulating the miR-142-3p/SOCS6/NF-κB signals. Therefore, the FGD5-AS1/miR-142-3p/SOCS6 axis may act as an important indicator in explaining the pathogenesis of periodontitis.

[Osteogenic effect of collagen/bioglass composites carrying noggin siRNA].

OBJECTIVE: To investigate osteogenic effect of collagen/bioglass composites loaded with a small interfering RNA (siRNA) targeting noggin. METHODS: The collagen/bioglass composites loaded with the negative control siRNA or noggin siRNA were prepared by freeze-drying method. CCK8 test was used to evaluate the proliferation of MC3T3 cells exposed to the aqueous extracts of collagen/bioglass composites and the siRNA-loaded collagen/bioglass composites. ALP activity assay, quantitative real-time PCR and Alizarin Red staining were used to assess the effect of the 3 composites on mineralization in MC3T3 cells. RESULTS: MC3T3 cells cultured for 3 and 5 days in the presence of the extracts of the 3 composites all showed significantly more active proliferation than the blank control cells (P < 0.05). Compared with the cells seeded on the scaffold without siRNA, MC3T3 cells seeded on collagen/bioglass scaffold loaded with noggin siRNA showed a significantly higher ALP activity at 14 days after seeding (P < 0.05) with significantly increased expression of ALP, Runx2 and BSP mRNAs (P < 0.05). Alizarin Red staining showed that the cells seeded on the noggin siRNA-loading collagen/bioglass scaffold contained significantly more mineralized nodules than the other cells (P < 0.05). CONCLUSIONS: The collagen/bioglass composites loaded with noggin siRNA have a good biocompatibility, and the collagen/bioglass composites and noggin siRNA show a synergistic effect in promoting osteogenesis.

Effect of personalized miniscrew-assisted rapid palatal expander on expansion of the median palatal suture in adults / 口腔疾病防治

Objective@# To investigate the manufacturing procedures of personalized miniscrew-assisted rapid palatal expanders (pMARPE) using digital technologies and to evaluate the effect of the expanders when expanding the midpalatal suture of an adult. @*Methods@# Digital technologies were used to make pMARPE, which was used to treat a 21-year-old woman with maxillary transverse deficiency (MTD). The relevant literature on MARPE was reviewed.@* Results@#PMARPE could be manufactured using intraoral digital scanning, computer-aided design and computer-aided manufacturing(CAD/CAM ), and 3D printing technologies. After expansion, the width of the anterior midpalatal suture, posterior midpalatal suture and maxillary skeletal width increased by 3.9 mm, 3.2 mm and 4.7 mm, respectively. There was no significant change in the inclination of maxillary first molars, and the height of alveolar ridge decreased slightly. It could be seen that using digital technologies to manufacture personalized expanders was possible for MARPE , and the initial stability of miniscrews played an important role in the expansion success rate, the increase of molar inclination is composed of many parts, and the decrease of alveolar ridge height may be overestimated due to the measurement method, as shown by a literature review. @*Conclusion@#The midpalatal suture of an adult patient with MTD could be expanded by pMARPE. However, the effect of this expander on the inclination of the first molar and alveolar bone height needs to be further studied with a larger sample size.

Orthodontic management of inverted and impacted bilateral maxillary central incisors: a case report.

Complete inversion and impaction of both permanent central incisors is uncommon and rarely reported in the literature. In this report, we describe the treatment of maxillary central incisors that were completely inverted and impacted and positioned high in the vestibule. The esthetic results achieved provide an alternative to extraction or surgical repositioning.