[Latest Findings on NOD-Like Receptor Family Pyrin Domain Containing Protein 3 Inflammasome and Bone and Articular Diseases].

Inflammasomes are important components of the innate immune system. They are assembled by cytoplasmic pattern recognition receptors and play a critical role in the pathogenesis and progression of various inflammatory diseases through regulating the release and activation of inflammatory cytokines and inducing cell prytosis. NOD-like receptor family pyrin domain containing protein 3 (NLRP3) inflammasome has been widely studied and has been shown to be closely associated with cardiovascular diseases and metabolic disorders. Bone and joint diseases, such as osteoarthritis and rheumatoid arthritis show high prevalence worldwide and can cause bone and cartilage damage, pain, and dysfunction, adversely affecting the patients' quality of life. The reported findings of some studies indicate that the pathogenesis of various bone and articular diseases is associated with NLRP3 inflammasome. Small molecule antagonists targeting NLRP3 inflammasome have shown considerable therapeutic potentials, but their clinical application still needs further exploration. Herein, we reviewed the composition and function of NLRP3 inflammasome and its association with bone and articular diseases.

[Porphyromonas gingivalis HmuY and Its Possible Effect on the Pathogenesis of Periodontitis].

Periodontitis, one of the most common inflammatory oral diseases in human beings, threatens the health of teeth and mouth and is closely associated with the development of many systemic diseases. Existing research about the pathogenesis of periodontitis mainly focuses on the oral microbial homeostasis and its complex interaction with the immune system. Among all the oral microorganisms, Porphyromonas gingivalis ( P. gingivalis) is considered to be the main pathogen causing chronic periodontitis. Recent studies have shown that P. gingivalis poesseses HmuY, a special heme binding protein, which binds with heme to provide essential nutrition for P. gingivalis and activates the host immune system. Therefore, HmuY plays an important role in the growth, proliferation, invasion, and pathogenesis of P. gingivalis and is a potential virulence factor of the bacteria. Existing studies on HmuY are limited to the host immune response that HmuY triggers, and there are still no conclusive findings on whether HmuY participates in the pathogenesis of periodontitis through other ways, such as influencing periodontal bone metabolism. Herein, we reviewed the latest research findings on the biological characteristics and physiological functions of HmuY and its relationship with chronic periodontitis, so as to provide new ideas for in-depth research and further explorations into the pathogenesis of chronic periodontitis.

[Research Progress in Mechanotransduction Process of Mechanical-Stress-Induced Autophagy].

As a self-protective mechanism for cells to obtain energy by degrading their own structures or substances, autophagy widely occurs in basic physiological process of all kinds of eukaryotic cells. In recent years, studies have shown that autophagy can be induced through a variety of mechanical transduction pathways when various tissues and cells are exposed to different types of mechanical stress, and cells and tissues involved can thus regulate cell metabolic functions and participate in the pathological process of a variety of diseases. The stress receptors on the cell membrane and the multiple signaling pathways and cytoskeletons have been shown to play an important role in this process. At present, due to the difficulties in the establishment of the stress loading model and the limitations in the research methods concerned, the specific mechanical transduction mechanisms of autophagy induced by mechanical stress is not clear. Therefore, more reliable in vitro and in vivo models and more advanced research methodology are needed to investigate the mechanical transduction process of autophagy induced by mechanical stress, and to promote ultimately progress in the understanding of autophagy-related diseases and their treatments. This article reviewed the regulatory role of mechanical stress on autophagy in physiological and disease processes and the signal transduction process related to autophagy induced by mechanical stress.

China experts' consensus on preventive and interceptive orthodontic treatments of malocclusions of children.

Malocclusion is one of the three most common oral diseases reported by World Health Organization(WHO). In China, its incidence rate is rising. Malocclusion seriously affects the dental and maxillofacial function, facial appearance and growth development of nearly 260 million children in China, and what is more, it affects their physical and mental health development. Malocclusion occurrence is related to genetic and environmental factors. Early treatment of malocclusion can create a good dental and maxillofacial development environment, correct abnormal growth and control the adverse effects of abnormal genetic factors. It can effectively reduce the prevalence of children's malocclusion and enhance their physical and mental health. This is an urgent need from the economic perspective of our society, so it has great practical and social significance. Experts from the project group "standard diagnose and treatment protocols for early orthodontic intervention of malocclusions of children" which initiated by China National Health Institute of Hospital Administration wrote the "China Experts' Consensus on Preventive and Interceptive Orthodontic Treatments of Malocclusions of Children", which aims to guide and popularize the clinical practice, improve the clinical theory and practice level, and accelerate the disciplinary development of early treatment of children's malocclusion in China. The consensus elaborates the harmfulness of malocclusion and the necessity of early treatment, and brings up the principles and fundamental contents. Based on the law of dental and maxillofacial development, this paper puts forward the guiding suggestions of preventive and interceptive treatments in different stages of dental development ranging from fetus to early permanent dentition. It is a systematic project to promote and standardize the early treatment of malocclusion. Through scientific and comprehensive stratified clinical practice and professional training, the clinical system of early treatment of malocclusion in China will eventually be perfected, so as to comprehensively care for children's dental and maxillofacial health, and improve their oral and physical health in China.

Osteogenesis, Osteoclastogenesis and their Crosstalk in Lipopolysaccharide-induced Periodontitis in Mice.

OBJECTIVE: To determine the crosstalk of osteogenesis and osteoclastogenesis of alveolar bone in lipopolysaccharide (LPS)-induced periodontitis in mice. METHODS: A representative periodontitis model was established by treating mice with LPS, and osteoblasts and osteoclasts were cultured. Osteoblasts and osteoclasts were cocultured to determine the effects of LPS on the crosstalk of osteogenesis and osteoclastogenesis. Quantitative polymerase chain reaction (qPCR) was performed to determine the expression of osteoclastogenesis makers underlying the potential mechanisms. RESULTS: The morphological and pathological changes in alveolar bone were observed in LPSinduced mice and LPS dose-dependently suppressed osteogenesis. The mRNA expression of cathepsin K, as a marker of osteoclasts, was accordingly downregulated in the coculture. The mRNA expression of osteoprotegerin was increased, while that of receptor activator of nuclear factor-κB ligand (RANKL) was decreased with an increased concentration of LPS. Moreover, the mRNA expression of toll-like receptor 4 (TLR4) was upregulated by LPS, whereas TLR4 knockout partially recovered osteoclast differentiation in the upper layer of the coculture. CONCLUSION: LPS dose-dependently suppressed osteogenesis but had a bidirectional effect on osteoclastogenesis. The combined effects of LPS on osteogenesis, osteoclastogenesis and their crosstalk via TLR4 account for alveolar bone loss in periodontitis.

[The Study of Signal Pathway Regulating the Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells].

Osteogenesis of mesenchymal stem cells to differentiate between bone marrow by multiple signaling pathways that control, directly or indirectly affect small related transcription factor 2 (runt-related transcription factor 2, Runx2) and osteoblast specific transcription factor (osterix, Osx), the expression of osteogenesis key transcription factors, such as in the development and regeneration of the bone, bone repair has played a key role in the process of reconstruction. These pathways play their mechanism of action, but also intertwined associated constitute a complex signal transduction network, but due to the limitations of research methods, the osteogenic differentiation related signaling pathways of the specific mechanism is still unclear, if you can clarify these different signaling pathways play to the role of their relevant mechanism and the relationship between various pathways and the mechanism study of osteogenesis differentiation is of great importance. This article will review the progress of various signaling pathways in the regulation of osteogenic differentiation of bone marrow mesenchymal stem cells.

[Screen and Function Study of the Key Regulative Odontogenic Genes in Mice].

OBJECTIVE: To screen the key odontogenic genes in mice and verify the odontogenic inducing effect on amniotic epithelial cells (WISH). METHODS: The spatially and temporally different expression of bone morphogenetic proteins 4 (BMP4), fibroblast growth factor 8 (FGF8), sonic hedgehog (SHH), lymphoid enhancer factor 1 (LEF1) proteins and their genes expression in the early odontogenesis stage (embryo day 10.5 (E10.5)、E11.5、E14.5) in fetal mice were detected by immunohistochemistry staining and quantitative real-time PCR (RT-qPCR). According to the results, we screened the probable key odontogenic genes. Then adding osteogenic inducing solution to induce non-odontogenic epithelium cells, WISH. After 3 weeks culture of non-odontogenic epithelial WISH for osteogenic induction, the epithelial-mesenchymal transformation cap ability was evaluated by using Alizarin (ALZ) red staining and RT-qPCR on the alkaline phosphatase ( ALP) mRNA expression level. Using germ layer recombination experiment to observe and verify whether the screened genes can induce non-odontogenic epithelium cells acquire odontogenesis ability. The recombined tissue grafts containing key genes were transplanted beneath the renal capsule of mice. RESULTS: The results of immunohistochemistry staining and RT-qPCR showed that on E10.5 BMP4 protein and gene were differently expressed in the first and second branchial arch epithelium, which synchronized the odontogenic capability transferring from epithelium to mesenchyme from E10.5-E14.5. Though the expression of FGF8 protein and gene existed such difference in the first and second branchial arch epithelium, there was no synchronization in transfer. The expression of LEF1 and SHH proteins and genes had neither difference nor synchronization. So far, we considered the BMP4 was the probable key odontogenic gene. Through 3 weeks' osteogenic induction, ALZ red stained positively and calcium nodules were observed in WISH, and the expression level of ALP mRNA increased. In the germ layer recombination experiment, exogenous BMP4 protein enabled the second branchial arch mesenchyme forming tooth-like structures after recombined with the second branchial arch epithelium or WISH. CONCLUSIONS: The proteins and genes of BMP4, FGF8, SHH and LEF1 are spatially and temporally differently expressed in the early tooth development stage in mice. The protein and gene of BMP4 are differently expressed between the first and second branchial arch epithelium and enables the non-odontogenic epithelium acquiring odontogenic ability. BMP4 is the possible key odontogenic gene.

Correction to: AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.

[This corrects the article DOI: 10.1038/boneres.2017.44.].

[Oral treatment for obstructive sleep apnea syndrome].

Obstructive sleep apnea syndrome (OSAS) is a common clinical disease with high incidence and low treating proportion, difficult evaluation, and complicated nosogenesis. OSAS can cause systematic impairments. Various treatment methods were applied in clinical setting with the tendency of cross-disciplinary promotion. Oral treatment plays an exceedingly important role in OSAS research and therapy. This study reports the oral treatment involving OSAS therapy.

AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.

AFF1 and AFF4 belong to the AFF (AF4/FMR2) family of proteins, which function as scaffolding proteins linking two different transcription elongation factors, positive elongation factor b (P-TEFb) and ELL1/2, in super elongation complexes (SECs). Both AFF1 and AFF4 regulate gene transcription through elongation and chromatin remodeling. However, their function in the osteogenic differentiation of mesenchymal stem cells (MSCs) is unknown. In this study, we show that small interfering RNA (siRNA)-mediated depletion of AFF1 in human MSCs leads to increased alkaline phosphatase (ALP) activity, enhanced mineralization and upregulated expression of osteogenic-related genes. On the contrary, depletion of AFF4 significantly inhibits the osteogenic potential of MSCs. In addition, we confirm that overexpression of AFF1 and AFF4 differentially affects osteogenic differentiation in vitro and MSC-mediated bone formation in vivo. Mechanistically, we find that AFF1 regulates the expression of DKK1 via binding to its promoter region. Depletion of DKK1 in HA-AFF1-overexpressing MSCs abrogates the impairment of osteogenic differentiation. Moreover, we detect that AFF4 is enriched in the promoter region of ID1. AFF4 knockdown blunts the BRE luciferase activity, SP7 expression and ALP activity induced by BMP2 treatment. In conclusion, our data indicate that AFF1 and AFF4 differentially regulate the osteogenic differentiation of human MSCs.

Nonsurgical treatment of an adult patient with bilateral posterior crossbite.

A woman with an Angle Class III malocclusion and bilateral posterior crossbites complaining of difficulty in chewing was treated orthodontically without surgery. The treatment comprised asymmetric extractions, a removable mandibular lingual arch constriction appliance to narrow the mandibular arch, and a standard edgewise appliance to align the teeth. Pretreatment, posttreatment, and 1-year follow-up records are shown. With this treatment strategy of constricting the mandibular arch by using a combination of removable and fixed orthodontic appliances, we achieved a good result with optimal occlusion.

[Response of bone marrow mesenchymal stem cells to mechanical stretch and gene expression of transforming growth factor-beta and insulin-like growth factor-II under mechanical strain].

OBJECTIVE: To study the response of rat bone marrow mesenchymal stem cells (MSCs) to a single period of mechanical strain and expression patterns of transforming growth factor-beta (TGF-beta) and insulin-like growth factor-II (IGF-II) after mechanical stretch. METHODS: Bone marrow MSCs were isolated from SD rats and cultured in vitro. A four-point bending apparatus were used to perform a single period of mechanical strain (2000 microepsilon, 40 min) on MSCs. Cellular proliferation and alkaline phosphatase (ALP) activity of MSCs were examined and gene expression patterns of TGF-beta and IGF-II were detected by SYBR green quantitative real-time RT-PCR. RESULTS: Cell proliferation, ALP activity and expression of TGF-beta and IGF-II were all significantly up-regulated in stretched MSCs when compared with their controls. The mRNA levels of TGF-beta and IGF-II got top increase immediately after mechanical loading and increased about 51.44 and 8.92 folds, respectively, when compared with control cells. Expression of TGF-beta and IGF-II decreased with time and returned to control level at 12 h after mechanical stimulus, despite of a small increase at 6 h. CONCLUSION: The mechanical stretch can promote MSCs proliferation, up-regulate its ALP activity and induce a time-dependent expression increase of TGF-beta and IGF-II which in turn result in osteogenic differentiation of MSCs. Mechanical stimulus is a key stimulator for osteogenic differentiation of MSCs and vital for bone formation in distraction osteogenesis.

Expression of bone-related genes in bone marrow MSCs after cyclic mechanical strain: implications for distraction osteogenesis.

AIM: Understanding the response of mesenchymal stem cells (MSCs) to mechanical strain and their consequent gene expression patterns will broaden our knowledge of the mechanobiology of distraction osteogenesis. METHODOLOGY: In this study, a single period of cyclic mechanical stretch (0.5 Hz, 2,000 microepsilon) was performed on rat bone marrow MSCs. Cellular proliferation and alkaline phosphatase (ALP) activity was examined. The mRNA expression of six bone-related genes (Ets-1, bFGF, IGF-II, TGF-beta, Cbfa1 and ALP) was detected using real-time quantitative RT-PCR. RESULTS: The results showed that mechanical strain can promote MSCs proliferation, increase ALP activity, and up-regulate the expression of these genes. A significant increase in Ets-1 expression was detected immediately after mechanical stimulation, but Cbfa1 expression became elevated later. The temporal expression pattern of ALP coincided perfectly with Cbfa1. CONCLUSION: The results of this study suggest that mechanical strain may act as a stimulator to induce differentiation of MSCs into osteoblasts, and that these bone-related genes may play different roles in the response of MSCs to mechanical stimulation.

[Temporospatial expression of bFGF and IGF-I in growing goats with cranial suture distraction osteogenesis].

OBJECTIVE: To investigate the expression patterns of bFGF and IGF-I in the growing goats with distracted cranial suture. METHODS: Coronal suture distraction was performed to 12 growing goats. The suture was expanded using a custom-made distractor with a rate of 0.4 mm/day for 8 days. Four goats were killed at 0, 2, and 4 weeks after the completion of suture distraction osteogenesis, respectively. The expanded sutures were harvested and processed for immunohistochemistry analysis of bFGF and IGF-I. Two goats without suture distraction were also examined as controls. RESULTS: The coronal sutures were expanded successfully. At 0 and 2 weeks after the completion of suture distraction, collagen fiber bundles were strengthened and aligned in the direction of the distraction. Strong expressions of bFGF and IGF-I were detected in the distracted sutures. Expressions of bFGF appeared in the fibroblast-like cells and the osteoblasts cells. Positive signal of IGF-I was mainly localized to the osteoblasts and the newly formed osteocytes. The strongest expressions of bFGF and IGF-I were found 0-2 weeks after the completion of the suture distraction. CONCLUSION: Distraction stimulates the production of bFGF and IGF-I, which may contribute to the formation and remodeling of new bones.

[Osteogenic differentiation of rat bone marrow mesenchymal stem cell after transfection with recombinant pAd-bone morphogenetic protein-7].

OBJECTIVE: To study the effect of recombinant pAd-BMP-7 on osteogenic differentiation of rat bone marrow mesenchymal stem cells (MSC). METHODS: Recombinant pAd-bone morphogenetic protein (BMP) 7 was constructed and the titer of recombinant adenovirus was determined. pAd-BMP-7 and pAdTrack-CMV were used to transfect rat MSC. Transfection efficiency was measured by fluorescent microscope and BMP-7 expression was detected by RT-PCR and immunocytochemical analysis. The MSC were then randomly divided into 3 groups: group A received pAd-BMP-7 transfection, group B was transfected with pAdTrack-CMV, and group C received pAdTrack-CMV transfection plus bone supplements. Osteogenic differentiation of MSC was evaluated by examination of mineralization nodes formation. RESULTS: The titer of pAd-BMP-7 reached about 2.0 x 10(15) pfu/L and transfection efficiency of exogenous gene was nearly 99% at day 2. The expression of exogenous gene sustained about 5 to 7 weeks, with a higher level during first 3 weeks. After transfection, transcription of BMP-7 and expression of BMP-7 protein were also verified in MSC. Compared with the negative results in group B, mineralization nodes were formed in both group A and group C. However, group A showed better formation of mineralization nodes than group C (P < 0.01). CONCLUSIONS: The results of this study indicated that recombinant pAd-BMP-7 can successfully transfect rat MSC and accelerate their osteogenic differentiation. The technique explored in this study provides a unique and valuable gene engineering approach for reconstruction of craniofacial bone defects.

[Effects of mesenchymal stem cells transplantation on cranial suture distraction osteogenesis in growing goats].

OBJECTIVE: To observe the effects of mesenchymal stem cells (MSCs)on cranial suture under mechanical strain in growing goats. METHODS: 10 growing goats were used in this study. A customized distractor was used for distraction of the coronal suture at a rate of 0.4 mm/day for 8 days. The experimental group(5 goats) was injected with autologous MSCs into the distracted region, whereas the control group (5 goats) with injection of physiological saline. All animals were killed at 4 weeks after the end of distraction. Scanning electron microscopy and histological analysis were taken to observe the samples. RESULTS: 4 weeks after the end of distraction, the cranial sutures in all animals were separated successfully. The new bone formation at the edge of suture in the experimental group was superior to that in the control group. CONCLUSION: Autologous MSCs transplantation may promote the cranial suture distraction osteogenesis in the growing goats.

[The changes of cytoskeleton F-actin in rat bone marrow mesenchymal stem cells and calvarial osteoblasts under mechanical strain].

OBJECTIVE: To explore the response of rat bone marrow mesenchymal stem cells (MSCs and calvarial osteoblasts to mechanical strain and the consequent changes of cytoskeleton F-actin. METHODS: Bone marrow MSCs and calvarial osteoblasts were isolated from SD rats and cultured in vitro. Mechanical stretch was performed on passage 3 cells at 2 000 microepsilon for 0, 2, 6 and 12 hours using four-point bending system. The response of cells and the distribution of F-actin were observed using fluorescent staining under laser scanning confocal microscope and the morphological parameters were quantified using image analysis software Laserpix. RESULTS: Under mechanical stretch, the fluorescent staining decreased obviously at both MSCs and osteoblasts, and F-actin filaments were rearranged and became tenuous, thinner, and abnormally distributed. The outline of nucleus became unclear and apoptotic changes were observed at some of both cells. Cellular size decreased more significantly in MSCs than in osteoblasts. Quantity analysis showed that total area of cells, total fluorescent density and green fluorescent density (F-actin) were all significantly decreased in MSCs (P < 0.05 or P < 0.01), and total fluorescent density, green fluorescent density and red fluorescent density (nuclei) did also in osteoblasts (P < 0.05 or P < 0.01). CONCLUSION: Mechanical stretch caused extensive response on both MSCs and osteoblasts which led to the rearrangement of F-actin filament and apoptosis in some of these cells. MSCs were more sensitive to mechanical strain than osteoblasts.

[Construction of recombinant plasmid pEGFP-BMP7 and its expression in rat bone marrow mesenchymal stem cells in vitro].

OBJECTIVE: To construct recombinant plasmid pEGFP-BMP7 and determine its expression in rat bone marrow mesenchymal stem cells (MSCs) in vitro. METHODS: cDNA of target gene was obtained from neonatal rat kidney by RT-PCR. After sequencing the target gene, the cDNA was subcloned into a eukaryote plasmid pEGFP-N1 by directed cloning and then digested with two restrictive endonucleases to verify the correctiveness of the recombinant plasmid pEGFP-BMP7. Rat bone marrow MSCs were transiently transfected with the pEGFP-BMP7 and transfection efficiency of the Green Fluorescent Protein (GFP) was determined. RT-PCR and immunocytochemical analysis were also performed to detect the expression of BMP7 in rat MSCs. RESULTS: 1 311 bp cDNA fragment was obtained by RT-PCR and sequence analysis showed it matched perfectly with that of rat BMP7 gene except a single nucleotide change at 756 bp from T to A. Digestion of the recombinant plasmid showed two 1.3 kb and 4.7 kb fragments and their size were same as those of BMP7 and pEGFP. This indicated that BMP7 cDNA was successfully subcloned into pEGFP. Transient transfection showed an efficiency of 33% at day 2 in rat MSCs. After transfection, transcription of BMP7 was detected in MSCs and expression of BMP7 protein was also verified. CONCLUSION: Recombinant eukaryote plasmid pEGFP-BMP7 was successfully constructed and expressed in rat bone marrow MSCs. This procedure may provide a unique method for stimulation of callus formation in distraction osteogenesis and reconstruction of craniofacial bone defects.