Defects of cohesin loader lead to bone dysplasia associated with transcriptional disturbance.

Cohesin loader nipped-B-like protein (Nipbl) is increasingly recognized for its important role in development and cancer. Cornelia de Lange Syndrome (CdLS), mostly caused by heterozygous mutations of Nipbl, is an autosomal dominant disease characterized by multiorgan malformations. However, the regulatory role and underlying mechanism of Nipbl in skeletal development remain largely elusive. In this study, we constructed a Nipbl-a Cas9-knockout (KO) zebrafish, which displayed severe retardation of global growth and skeletal development. Deficiency of Nipbl remarkably compromised cell growth and survival, and osteogenic differentiation of mammalian osteoblast precursors. Furthermore, Nipbl depletion impaired the cell cycle process, and caused DNA damage accumulation and cellular senescence. In addition, nucleolar fibrillarin expression, global rRNA biogenesis, and protein translation were defective in the Nipbl-depleted osteoblast precursors. Interestingly, an integrated stress response inhibitor (ISRIB), partially rescued Nipbl depletion-induced cellular defects in proliferation and apoptosis, osteogenesis, and nucleolar function. Simultaneously, we performed transcriptome analysis of Nipbl deficiency on human neural crest cells and mouse embryonic fibroblasts in combination with Nipbl ChIP-Seq. We found that Nipbl deficiency caused thousands of differentially expressed genes including some important genes in bone and cartilage development. In conclusion, Nipbl deficiency compromised skeleton development through impairing osteoblast precursor cell proliferation and survival, and osteogenic differentiation, and also disturbing the expression of some osteogenesis-regulatory genes. Our study elucidated that Nipbl played a pivotal role in skeleton development, and supported the fact that treatment of ISRIB may provide an early intervention strategy to alleviate the bone dysplasia of CdLS.

PLGA-based control release of Noggin blocks the premature fusion of cranial sutures caused by retinoic acid.

Craniosynostosis (CS), the premature and pathological fusion of cranial sutures, is a relatively common developmental disorder. Elucidation of the pathways involved and thus therapeutically targeting it would be promising for the prevention of CS. In the present study, we examined the role of BMP pathway in the all-trans retinoic acid (atRA)-induced CS model and tried to target the pathway in vivo via PLGA-based control release. As expected, the posterior frontal suture was found to fuse prematurely in the atRA subcutaneous injection mouse model. Further mechanism study revealed that atRA could repress the proliferation while promote the osteogenic differentiation of suture-derived mesenchymal cells (SMCs). Moreover, BMP signal pathway was found to be activated by atRA, as seen from increased expression of BMPR-2 and pSMAD1/5/9. Recombinant mouse Noggin blocked the atRA-induced enhancement of osteogenesis of SMCs in vitro. In vivo, PLGA microsphere encapsulated with Noggin significantly prevented the atRA-induced suture fusion. Collectively, these data support the hypothesis that BMP signaling is involved in retinoic acid-induced premature fusion of cranial sutures, while PLGA microsphere-based control release of Noggin emerges as a promising strategy for prevention of atRA-induced suture fusion.

Contribution of the mandible position to the facial profile perception of a female facial profile: An eye-tracking study.

INTRODUCTION: Studies concerning the visual attention of laypersons viewing the soft tissue facial profile of men and women with malocclusion are lacking. This study aimed to determine the visual attention to the facial profile of patients with different levels of mandibular protrusion and facial background attractiveness using an eye-tracking device. METHODS: The scanning paths of 54 Chinese laypersons (50% female, 50% male, aged 18-23 years) were recorded by an eye-tracking device when they observed composite female facial profile images (n = 24), which were combinations of different degrees of mandibular protrusion (normal, slight, moderate, and severe) and different levels of facial background attractiveness (attractive, average, and unattractive). Dependent variables (fixation duration and first fixation time) were analyzed using repeated-measures factorial analysis of variance. RESULTS: For normal mandibular profiles, the fixation duration of the eyes was significantly higher than that of other facial features (P <0.001). The lower face and nose received the least attention. As the degree of protrusion increased from slight to moderate, more attention was drawn to the lower face accompanied by less attention to eyes in the unattractive group (P <0.05). When protrusion degree increased from moderate to severe, attention shifted from nose to lower face significantly in the attractive group (P <0.05). Attention shift from eyes to lower face was also found in the average group when protrusion degree rose to moderate protrusion from normal profile (P <0.05). A significant interaction between facial attractiveness and mandibular protrusion was found in the lower face duration (P = 0.020). The threshold point (the point of mandibular protrusion degree that evoked attention to the lower face) of the attractive facial background was higher than that of the unattractive background. Once evoked, the effect of mandibular protrusion of the attractive group tended to be stronger than that of the unattractive group, though without statistical difference. CONCLUSIONS: Eyes are the most salient area. The increasing degree of mandibular protrusion tends to draw attention to the lower face from other facial features. Background attractiveness can modify this behavior.

Objective method for evaluating orthodontic treatment from the lay perspective: An eye-tracking study.

INTRODUCTION: Currently, few methods are available to measure orthodontic treatment need and treatment outcome from the lay perspective. The objective of this study was to explore the function of an eye-tracking method to evaluate orthodontic treatment need and treatment outcome from the lay perspective as a novel and objective way when compared with traditional assessments. METHODS: The scanpaths of 88 laypersons observing the repose and smiling photographs of normal subjects and pretreatment and posttreatment malocclusion patients were recorded by an eye-tracking device. The total fixation time and the first fixation time on the areas of interest (eyes, nose, and mouth) for each group of faces were compared and analyzed using mixed-effects linear regression and a support vector machine. The aesthetic component of the Index of Orthodontic Treatment Need was used to categorize treatment need and outcome levels to determine the accuracy of the support vector machine in identifying these variables. RESULTS: Significant deviations in the scanpaths of laypersons viewing pretreatment smiling faces were noted, with less fixation time (P <0.05) and later attention capture (P <0.05) on the eyes, and more fixation time (P <0.05) and earlier attention capture (P <0.05) on the mouth than for the scanpaths of laypersons viewing normal smiling subjects. The same results were obtained when comparing posttreatment smiling patients, with less fixation time (P <0.05) and later attention capture on the eyes (P <0.05), and more fixation time (P <0.05) and earlier attention capture on the mouth (P <0.05). The pretreatment repose faces exhibited an earlier attention capture on the mouth than did the normal subjects (P <0.05) and posttreatment patients (P <0.05). Linear support vector machine classification showed accuracies of 97.2% and 93.4% in distinguishing pretreatment patients from normal subjects (treatment need), and pretreatment patients from posttreatment patients (treatment outcome), respectively. CONCLUSIONS: The eye-tracking device was able to objectively quantify the effect of malocclusion on facial perception and the impact of orthodontic treatment on malocclusion from the lay perspective. The support vector machine for classification of selected features achieved high accuracy of judging treatment need and treatment outcome. This approach may represent a new method for objectively evaluating orthodontic treatment need and treatment outcome from the perspective of laypersons.

Translation and validation of the Chinese version of the psychosocial impact of dental aesthetics questionnaire.

The psychosocial impact of dental aesthetics questionnaire (PIDAQ) could reflect dental aesthetic degrees evaluated by traditional dental aesthetic indices. However, no Chinese version of PIDAQ has been used. The aim of this study was to translate the original English version of PIDAQ into Chinese and to assess the validity and reliability of the Chinese version for application in Chinese young adults. The questionnaire was translated into Chinese, back translated, pre-tested, and cross-culturally adapted. Subsequently, the Chinese version of PIDAQ along with two other scales, the aesthetic component of Index of Orthodontic Treatment Need and the Perception of Occlusion Scale, were administered to 436 young adults from the city of Guangzhou, China. Two hundred and twenty-five of them perceived 'have demand' for orthodontics and 221 perceived 'no demand'. Cronbach's alpha of the translated PIDAQ was 0.94, corrected item-total correlation ranged from 0.39 to 0.81. The 23 items of PIDAQ were divided into three domains. There was a logical relation between the items in the same domain and a highly significant association between scores of PIDAQ and the two other scales. The 'have demand' group scored significantly higher than the 'no demand' group using PIDAQ (P < 0.01). The translated Chinese version of PIDAQ demonstrated good reliability, validity, and responsiveness. Its sufficient discriminative and evaluative psychometric properties provide the theoretical evidence for further use in study on orthodontic-specific aspects of quality of life among Chinese young adults.

Aesthetic perception and factors associated with dentofacial midline awareness.

AIMS: To examine orthodontic patients' aesthetic perception and factors likely to influence the detection of a dentofacial midline discrepancy. METHODS: An electronic questionnaire was designed to invite an orthodontic population to evaluate and select an ideal value, a detectable value and a tolerable value from a series of images exhibiting a dentofacial midline discrepancy. A binary logistic regression analysis was performed to evaluate possible influencing factors. RESULTS: A barely discernabe dentofacia midline discrepancy ranged between -0.020 +/- 0.38 mm. The personal characteristics of the evaluators appeared to have no appreciable effect at this level. A detectable value was 1.33 +/- 0.63 mm and the education level, orthodontic history and malocclusion severity were influencing factors amongst the assessors. A tolerable value was 2.63 +/- 0.94 mm and influencing factors included the education level and the malocclusion severity of the evaluators. CONCLUSION: The barely discernable value, detectable value and tolerable value could be used to quantify the aesthetic perception of orthodontic patients regarding a dentofacia midline discrepancy. The aesthetic perception was influenced by observer education level, orthodontic history and personal malocclusion severity, but not by age, gender, and subjective evaluation of dentofacial appearance.

Total mesialization of the mandibular dentition using a mini-implant-supported device : A finite element analysis.

PURPOSE: Total mandibular arch mesialization using mini-implants is challenging due to anatomic limitations. The aim of this study was to introduce a mini-implant-supported device for total mesialization of the mandibular dentition and to analyze the biomechanical properties of the device. METHODS: Finite element models were constructed to explore the effect of friction and force direction on the force transmission efficiency of the device. In addition, the three-dimensional displacement of each tooth was evaluated with two force application points (2 or 8 mm hooks) under three force conditions (symmetric: 150 g of force on both sides, or asymmetric: 100 and 200 g of force on each side). RESULTS: The force transmission efficiency was 66.7% under a friction coefficient of 0.15 and parallel pushing and pulling forces. The force transmission efficiency was 65.90 and 66.63% when the pushing force was 15° away from the pulling force on the sagittal and horizontal planes, respectively. The mandibular dentition moved mesially with a greater tendency for incisor labial crown tipping, mesial molar rotation and buccal second molar crown tipping when using the 8 mm hook compared to that when using the 2 mm hook. Rigid archwires resulted in more consistent tooth mesialization than stainless steel archwires. Asymmetric forces resulted in asymmetric dental arch mesialization. CONCLUSION: The forces transmitted by the presented mini-implant-supported device varied depending on the friction level and force direction. The device should be able to achieve symmetric or asymmetric total mesialization of the mandibular dentition.

Activation of NLRP3 signaling contributes to cadmium-induced bone defects, associated with autophagic flux obstruction.

Cadmium (Cd) is a widespread environmental and industrial pollutant to cause various bone metabolic diseases. Our former study reported that Cd promoted adipogenesis and inhibited osteogenic differentiation of primary bone marrow-derived mesenchymal stem cells (BMSCs) by NF-κB inflammation signaling and oxidative stress, and Cd-induced osteoporosis of long bone and compromised repair of cranial bone defect in vivo. However, the underlying mechanisms of Cd-induced bone damage remain elusive. In this study, we used Sprague Dawley (SD) rat and NLRP3-knockout mouse models to elucidate the exact effects and molecular mechanisms of Cd-induced bone damage and aging. Herein we found that the exposure of Cd preferentially targeted a few specific tissues such as bone and kidney. Cd triggered NLRP3 inflammasome pathways and the accumulation of autophagosomes of primary BMSCs, and also Cd stimulated the differentiation and bone resorption function of primary osteoclasts. Moreover, Cd not only activated ROS/NLRP3/caspase-1/p20/IL-1ß pathways, but also influenced Keap1/Nrf2/ARE signaling. The data revealed that autophagy dysfunction and NLRP3 pathways synergistically mediated the impairments of Cd in bone tissues. Loss of NLRP3 function partially alleviated Cd-induced osteoporosis and craniofacial bone defect in the NLRP3-knockout mouse model. Furthermore, we characterized the protective effects and potential therapeutic targets of the combined treatment of anti-aging agents (rapamycin+melatonin+NLRP3 selective inhibitor MCC950) on Cd-induced bone damage and inflammatory aging. These results illuminate that ROS/NLRP3 pathways and autophagic flux obstruction are involved in the Cd-induced toxic actions of bone tissues. Collectively, our study unveils some therapeutic targets and the regulatory mechanism to prevent Cd-caused bone rarefaction. The findings improve the mechanistic understanding of environmental Cd exposure-caused bone metabolism disorders and tissue damage.

Repurposing Dihydroartemisinin to Combat Oral Squamous Cell Carcinoma, Associated with Mitochondrial Dysfunction and Oxidative Stress.

Oral squamous cell carcinoma (OSCC), with aggressive locoregional invasion, has a high rate of early recurrences and poor prognosis. Dihydroartemisinin (DHA), as a derivative of artemisinin, has been found to exert potent antitumor activity. Recent studies reported that DHA suppresses OSCC cell growth and viability through the regulation of reactive oxygen species (ROS) production and mitochondrial calcium uniporter. However, the mechanism underlying the action of DHA on OSCCs remains elusive. In the study, we observed that 159 genes were remarkably misregulated in primary OSCC tumors associated with DHA-inhibited pathways, supporting that OSCCs are susceptible to DHA treatment. Herein, our study showed that DHA exhibited promising effects to suppress OSCC cell growth and survival, and single-cell colony formation. Interestingly, the combination of DHA and cisplatin (CDDP) significantly reduced the toxicity of CDDP treatment alone on human normal oral cells (NOK). Moreover, DHA remarkably impaired mitochondrial structure and function, and triggered DNA damage and ROS generation, and activation of mitophagy. In addition, DHA induced leakage of cytochrome C and apoptosis-inducing factor (AIF) from mitochondria, elevated Bax/cleaved-caspase 3 expression levels and compromised Bcl2 protein expression. In the OSCC tumor-xenograft mice model, DHA remarkably suppressed tumor growth and induced apoptosis of OSCCs in vivo. Intriguingly, a selective mitophagy inhibitor Mdivi-1 could significantly reinforce the anticancer activity of DHA treatment. DHA and Mdivi-1 can synergistically suppress OSCC cell proliferation and survival. These data uncover a previously unappreciated contribution of the mitochondria-associated pathway to the antitumor activity of DHA on OSCCs. Our study shed light on a new aspect of a DHA-based therapeutic strategy to combat OSCC tumors.

Cadmium exposure induces osteoporosis through cellular senescence, associated with activation of NF-κB pathway and mitochondrial dysfunction.

Cadmium (Cd) is a heavy metal toxicant as a common pollutant derived from many agricultural and industrial sources. The absorption of Cd takes place primarily through Cd-contaminated food and water and, to a significant extent, via inhalation of Cd-contaminated air and cigarette smoking. Epidemiological data suggest that occupational or environmental exposure to Cd increases the health risk for osteoporosis and spontaneous fracture such as itai-itai disease. However, the direct effects and underlying mechanism(s) of Cd exposure on bone damage are largely unknown. We used primary bone marrow-derived mesenchymal stromal cells (BMMSCs) and found that Cd significantly induced BMMSC cellular senescence through over-activation of NF-κB signaling pathway. Increased cell senescence was determined by production of senescence-associated secretory phenotype (SASP), cell cycle arrest and upregulation of p21/p53/p16INK4a protein expression. Additionally, Cd impaired osteogenic differentiation and increased adipogenesis of BMMSCs, and significantly induced cellular senescence-associated defects such as mitochondrial dysfunction and DNA damage. Sprague-Dawley (SD) rats were chronically exposed to Cd to verify that Cd significantly increased adipocyte number, and decreased mineralization tissues of bone marrow in vivo. Interestingly, we observed that Cd exposure remarkably retarded bone repair and regeneration after operation of skull defect. Notably, pretreatment of melatonin is able to partially prevent Cd-induced some senescence-associated defects of BMMSCs including mitochondrial dysfunction and DNA damage. Although Cd activated mammalian target of rapamycin (mTOR) pathway, rapamycin only partially ameliorated Cd-induced cell apoptosis rather than cellular senescence phenotypes of BMMSCs. In addition, a selective NF-κB inhibitor moderately alleviated Cd-caused the senescence-related defects of the BMMSCs. The study shed light on the action and mechanism of Cd on osteoporosis and bone ageing, and may provide a novel option to ameliorate the harmful effects of Cd exposure.

[Investigation on profile self-perception of lower anterior facial height by patients seeking orthodontic treatment].

PURPOSE: To investigate the profile self-perception of lower anterior facial height(LAFH) by patients seeking orthodontic treatment, and explore the influencial factors. METHODS: Profile photographs of two Chinese adults (one female and one male with normal profiles) were digitized to create two baseline templates. Changes in middle anterior facial height / lower anterior facial height ratio were made on the templates by altering lower anterior facial height from 0.5 to 1.5 in 0.1 increments. An electronic questionnaire survey was conducted among patients who met the sample criteria. They were asked to choose one from various photos that most resembled their own profile. Then profile photos of patients were taken and measured. Differences between self-perception profile and actual profile were compared using paired t test. Statistical analysis was employed for comparison between different age, genders, profile concerns, education backgrounds, orthodontic histories, marital status and facial types with SPSS 17.0 software package. RESULTS: Two hundred and twenty-six subjects (average age 19.2±6.0 years; 79 men, 147 women) were interviewed in this survey. The ratio of self-perception profile by the patients was lower than actual. Difference was significant between patients' actual profile and self-perception profile(P<0.01).Among the seven factors，profile concerns（P<0.01） and orthodontic history (P=0.002) were significantly correlated with profile self-perception of lower anterior facial height by the patients． CONCLUSIONS: There is a cognitive bias in profile self-perception of lower anterior facial height by patients seeking orthodontic treatment. The patients' self-perception of lower anterior facial height is influenced by profile concerns and orthodontic history, not by age, sex, education backgrounds, marital status and facial types.

Tooth Regeneration: Insights from Tooth Development and Spatial-Temporal Control of Bioactive Drug Release.

Tooth defect and tooth loss are common clinical diseases in stomatology. Compared with the traditional oral restoration treatment, tooth regeneration has unique advantages and is currently the focus of oral biomedical research. It is known that dozens of cytokines/growth factors and other bioactive factors are expressed in a spatial-temporal pattern during tooth development. On the other hand, the technology for spatial-temporal control of drug release has been intensively studied and well developed recently, making control release of these bioactive factors mimicking spatial-temporal pattern more feasible than ever for the purpose of tooth regeneration. This article reviews the research progress on the tooth development and discusses the future of tooth regeneration in the context of spatial-temporal release of developmental factors.

Optogenetic control of mesenchymal cell fate towards precise bone regeneration.

Rationale: Spatial-temporal control of cell fate in vivo is of great importance for regenerative medicine. Currently, there remain no practical strategies to tune cell-fate spatial-temporally. Optogenetics is a biological technique that widely used to control cell activity in genetically defined neurons in a spatiotemporal-specific manner by light. In this study, optogenetics was repurposed for precise bone tissue regeneration. Methods: Lhx8 and BMP2 genes, which are considered as the master genes for mesenchymal stem cell proliferation and differentiation respectively, were recombined into a customized optogenetic control system. In the system, Lhx8 was constitutively expressed, while BMP2 together with shLhx8 expression was driven by blue light. Results: As expected, blue light induced BMP2 expression and inactivated Lhx8 expression in cells infected with the optogenetic control system. Optogenetic control of BMP2 and Lhx8 expression inversely regulates MSC fate in vitro. By animal study, we found that blue light could fine-tune the regeneration in vivo. Blue light illumination significantly promotes bone regeneration when the scaffold was loaded with MSCs infected with adeno-Lhx8, GI-Gal4DBD, LOV-VP16, and BMP2-shLhx8. Conclusions: Together, our study revealed that optogenetic control of the master genes for mesenchymal stem cell proliferation and differentiation would be such a candidate strategy for precise regenerative medicine.

[Perception of facial profile attractiveness of lower anterior face height in orthodontic treatment seeking people].

OBJECTIVE: To evaluate the most acceptable lower anterior face height of male and female by orthodontic treatment seeking people. METHODS: Two hundred and thirty-two Chinese orthodontic seeking people of Guanghua Hospital of Stomatology of Sun Yat-sen University were randomly selected in this survey. An electronic questionnaire was designed with a set of male and female young Chinese adult images with changes of the lower anterior face height (while the middle anterior face height remains the same). They were asked about the lowest, highest and optimal proportion (or so-called lower, higher and optimum limits respectively) between the lower anterior face height and the middle anterior face height (LAFH/MAFH) they could accept. All the findings of the proportion were analyzed by a statistic system. RESULTS: The lower limits' median value in regard to the LAFH/MAFH of male model and female model images was 0.8, this limit value for the male model's was greater than the female model's (P = 0.039); the higher limits' median value was 1.1, this limit value for the male model's was less than the female model's (P < 0.001); the optimum limits' median value was 0.9, this limit value for the male model's was greater than the female model's (P < 0.001). CONCLUSION: The result of this study shows all lower, higher and optimal limits accepted by the orthodontic treatment seeking people in regard to the proportion between the lower and middle height of anterior faces. This result will facilitate the understanding of aesthetic judgments of orthodontic patients on profile lower anterior facial height for orthodontist in treatments.

[Investigation on facial profile preferences of orthodontic patients].

PURPOSE: To investigate facial profile preferences of orthodontic patients and determine whether the patient's age and sex were influential factors in the esthetic perception for providing reference for clinical practice. METHODS: Profile digital photographs of each patient were used. Changes in facial convexity were established by altering the position of mandible incrementally with Photoshop 7.0. Thus profile images of various degrees of mandiblular anteroposterior discrepancy for each patient was generated. Then an electronic questionnaire was designed and administered to investigate tolerable boundary values for mandibular retrognathism, tolerable boundary values for mandibular prognathism and most pleasing profiles of 203 subjects (average age 19.2±6.0 years; 70 males, 133 females). Differences between male and female profiles in the esthetic perception of patients were analyzed by Wilcoxon matched-pairs signed ranks test. Comparison of esthetics perception for male and female profiles regarding patient's sex and age was made by Wilcoxon rank sum test of two independent samples. All statistical analysis was performed using SPSS 17.0 software package. RESULTS: The zone of acceptability of facial convexity was 168°-180° for male model and 160°-172° for female model. The most pleasing profile was 172° for male and 168° for female. There was no significant difference between male and female patients in facial profile preferences (P>0.05). The differences in facial profile preferences between adult group and immature group were statistically significant (P<0.05). In the comparison of age groups, the adult group preferred bigger facial convexity angles than immature group for male and female retrognathia profile, male prognathia profile and male most pleasing profile. CONCLUSIONS: The zone of acceptability of facial convexity and the most pleasing profile exist in patients' esthetic perception of profile. There is difference between male and female profiles in the esthetic perception. The facial profile preferences of orthodontic patients are influenced by age, not by sex.