Microenvironmental stiffness mediates cytoskeleton re-organization in chondrocytes through laminin-FAK mechanotransduction / 国际口腔科学杂志·英文版

Microenvironmental biophysical factors play a fundamental role in controlling cell behaviors including cell morphology, proliferation, adhesion and differentiation, and even determining the cell fate. Cells are able to actively sense the surrounding mechanical microenvironment and change their cellular morphology to adapt to it. Although cell morphological changes have been considered to be the first and most important step in the interaction between cells and their mechanical microenvironment, their regulatory network is not completely clear. In the current study, we generated silicon-based elastomer polydimethylsiloxane (PDMS) substrates with stiff (15:1, PDMS elastomer vs. curing agent) and soft (45:1) stiffnesses, which showed the Young's moduli of ~450 kPa and 46 kPa, respectively, and elucidated a new path in cytoskeleton re-organization in chondrocytes in response to changed substrate stiffnesses by characterizing the axis shift from the secreted extracellular protein laminin β1, focal adhesion complex protein FAK to microfilament bundling. We first showed the cellular cytoskeleton changes in chondrocytes by characterizing the cell spreading area and cellular synapses. We then found the changes of secreted extracellular linkage protein, laminin β1, and focal adhesion complex protein, FAK, in chondrocytes in response to different substrate stiffnesses. These two proteins were shown to be directly interacted by Co-IP and colocalization. We next showed that impact of FAK on the cytoskeleton organization by showing the changes of microfilament bundles and found the potential intermediate regulators. Taking together, this modulation axis of laminin β1-FAK-microfilament could enlarge our understanding about the interdependence among mechanosensing, mechanotransduction, and cytoskeleton re-organization.

circ_0003204 regulates the osteogenic differentiation of human adipose-derived stem cells via miR-370-3p/HDAC4 axis / 国际口腔科学杂志·英文版

Human adipose-derived stem cells (hASCs) are a promising cell type for bone tissue regeneration. Circular RNAs (circRNAs) have been shown to play a critical role in regulating various cell differentiation and involve in mesenchymal stem cell osteogenesis. However, how circRNAs regulate hASCs in osteogenesis is still unclear. Herein, we found circ_0003204 was significantly downregulated during osteogenic differentiation of hASCs. Knockdown of circ_0003204 by siRNA or overexpression by lentivirus confirmed circ_0003204 could negatively regulate the osteogenic differentiation of hASCs. We performed dual-luciferase reporting assay and rescue experiments to verify circ_0003204 regulated osteogenic differentiation via sponging miR-370-3p. We predicted and confirmed that miR-370-3p had targets in the 3'-UTR of HDAC4 mRNA. The following rescue experiments indicated that circ_0003204 regulated the osteogenic differentiation of hASCs via miR-370-3p/HDAC4 axis. Subsequent in vivo experiments showed the silencing of circ_0003204 increased the bone formation and promoted the expression of osteogenic-related proteins in a mouse bone defect model, while overexpression of circ_0003204 inhibited bone defect repair. Our findings indicated that circ_0003204 might be a promising target to promote the efficacy of hASCs in repairing bone defects.

Parathyroid hormone increases alveolar bone homoeostasis during orthodontic tooth movement in rats with periodontitis via crosstalk between STAT3 and β-catenin / 国际口腔科学杂志·英文版

Periodontitis patients are at risk of alveolar bone loss during orthodontic treatment. The aim of this study was to investigate whether intermittent parathyroid hormone (1-34) treatment (iPTH) could reduce alveolar bone loss during orthodontic tooth movement (OTM) in individuals with periodontitis and the underlying mechanism. A rat model of OTM in the context of periodontitis was established and alveolar bone loss was observed. The control, iPTH and iPTH + stattic groups received injections of vehicle, PTH and vehicle, or PTH and the signal transducer and activator of transcription 3 (STAT3) inhibitor stattic, respectively. iPTH prevented alveolar bone loss by enhancing osteogenesis and suppressing bone resorption in the alveolar bone during OTM in rats with periodontitis. This effect of iPTH was along with STAT3 activation and reduced by a local injection of stattic. iPTH promoted osteoblastic differentiation and might further regulate the Wnt/β-catenin pathway in a STAT3-dependent manner. The findings of this study suggest that iPTH might reduce alveolar bone loss during OTM in rats with periodontitis through STAT3/β-catenin crosstalk.

AFF4 regulates osteogenic differentiation of human dental follicle cells / 国际口腔科学杂志·英文版

As a member of the AFF (AF4/FMR2) family, AFF4 is a transcription elongation factor that is a component of the super elongation complex. AFF4 serves as a scaffolding protein that connects transcription factors and promotes gene transcription through elongation and chromatin remodelling. Here, we investigated the effect of AFF4 on human dental follicle cells (DFCs) in osteogenic differentiation. In this study, we found that small interfering RNA-mediated depletion of AFF4 resulted in decreased alkaline phosphatase (ALP) activity and impaired mineralization. In addition, the expression of osteogenic-related genes (DLX5, SP7, RUNX2 and BGLAP) was significantly downregulated. In contrast, lentivirus-mediated overexpression of AFF4 significantly enhanced the osteogenic potential of human DFCs. Mechanistically, we found that both the mRNA and protein levels of ALKBH1, a critical regulator of epigenetics, changed in accordance with AFF4 expression levels. Overexpression of ALKBH1 in AFF4-depleted DFCs partially rescued the impairment of osteogenic differentiation. Our data indicated that AFF4 promoted the osteogenic differentiation of DFCs by upregulating the transcription of ALKBH1.

Compliant substratum modulates vinculin expression in focal adhesion plaques in skeletal cells / 国际口腔科学杂志·英文版

The biophysical properties of the extracellular matrix (ECM) dictate tissue-specific cell behaviour. In the skeleton system, bone shows the potential to adapt its architecture and contexture to environmental rigidity via the bone remodelling process, which involves chondrocytes, osteoblasts, osteoclasts, osteocytes and even peripheral bone marrow-derived stem/stromal cells (BMSCs). In the current study, we generated stiff (~1 014 ± 56) kPa, Young's modulus) and soft (~46 ± 11) kPa silicon-based elastomer polydimethylsiloxane (PDMS) substrates by mixing curing agent into oligomeric base at 1:5 and 1:45 ratios, respectively, and investigated the influence of substrate stiffness on the cell behaviours by characterizing cell spreading area, cell cytoskeleton and cell adhesion capacity. The results showed that the cell spreading areas of chondrocytes, osteoblasts, osteoclasts, osteocytes and BMSCs were all reduced in the soft substrate relative to those in the stiff substrate. F-actin staining confirmed that the cytoskeleton was also changed in the soft group compared to that in the stiff group. Vinculin in focal adhesion plaques was significantly decreased in response to soft substrate compared to stiff substrate. This study establishes the potential correlation between microenvironmental mechanics and the skeletal system, and the results regarding changes in cell spreading area, cytoskeleton and cell adhesion further indicate the important role of biomechanics in the cell-matrix interaction.

Influence of "Mental Health Law of the People's Republic of China" on psychological counseling in colleges and universities: An interview study on the heads of psychological counseling centers in colleges and universities in Beijing / 中国心理卫生杂志

Objective:To investigate the impact of China's Mental Health Law on the work of psychological counseling in colleges and universities, and to explore ways to improve the law. Methods: Totally 12 heads of college and university counseling centers in Beijing were conducted with semi-structured interviews. The average age of the interviewees was (40 ±7) years old, with master or doctor degrees in psychology or related disciplines. The method of content analysis was used to analyze the interviewees' understanding of the " Mental Health Law". Results: All of the 12 interviewees had gained some understanding of the "Mental Health Law", and accordingly amended the regulation of their counseling centers. Also, interviewees suggested the positive and negative impacts brought by the law, such as enhancing practitioners' legislative sense, clarifying their responsibilities and boundaries as college and university counseling, as well as difficulties to distinguish psychotherapy and psychological counseling, ambiguity in the legality of working with students who were diagnosed with mental disorders. Moreover, interviewees threw out suggestions on improving the law from the aspect of industry standard, supervision department and vocational qualification. Conclusion: The execution of "Mental Health Law" improves practitioners' legislative sense, clarifies their responsibility. Nevertheless, it does not clearly distinguish psychotherapy from psychological counseling, and be lack of regulation on the psychological counseling industry.

Effects on glucose control of abnormal glucose metabolism during pregnancy by continuous glucose monitoring system / 中华全科医师杂志

For the case study group,52 pregnant women diagnosed as abnormal glucose metabolism and requiring in-hospital glucose control were selected for continuous glucose monitoring.And another 49 pregnant women with known glucose levels through serial glucose monitoring at the same period were taken as case control group.We divided the case study group into A1,A2 and B based on White's typing.In case study group,the glucose levels peaked at 8 to 10 am and dropped to the lowest levels at 10 pm to 6 am on the next day.The glucose of A2 group was markedly higher than that of A1 group.The highest postprandial glucose of case study group happens at (1.6 ± 0.5) h after breakfast,(1.6 ± 1.2) h after lunch and (1.6 ± 0.8) h after dinner.The blood glucose wavy coefficient of patients of A1 and A2 groups had significant statistical difference.The newborn weight of case study group was lower than that of case control group.