Involvement of microRNA-4680-3p against phenytoin-induced cell proliferation inhibition in human palate cells.

Cleft palate (CP) is one of the most common birth defects and is caused by a combination of genetic and/or environmental factors. Environmental factors such as pharmaceutical exposure in pregnant women are known to induce CP. Recently, microRNA (miRNA) was found to be affected by environmental factors. The aim of the present study was to investigate the involvement of miRNA against phenytoin (PHE)-induced inhibition of proliferation in human embryonic palatal mesenchymal (HEPM) cells. We demonstrated that PHE inhibited HEPM cell proliferation in a dose-dependent manner. We found that treatment with PHE downregulated cyclin-D1 and cyclin-E expressions in HEPM cells. Furthermore, PHE increased miR-4680-3p expression and decreased two downstream genes (ERBB2 and JADE1). Importantly, an miR-4680-3p-specific inhibitor restored HEPM cell proliferation and altered expression of ERBB2 and JADE1 in cells treated with PHE. These results suggest that PHE suppresses cell proliferation via modulation of miR-4680-3p expression.

Protective effect of Sasa veitchii extract against all-trans-retinoic acid-induced inhibition of proliferation of cultured human palate cells.

Cleft palate is the most common facial birth defect worldwide. It is caused by environmental factors or genetic mutations. Environmental factors such as pharmaceutical exposure in women are known to induce cleft palate. The aim of the present study was to investigate the protective effect of Sasa veitchii extract against medicine-induced inhibition of proliferation of human embryonic palatal mesenchymal cells. We demonstrated that all-trans-retinoic acid inhibited human embryonic palatal mesenchymal cell proliferation in a dose-dependent manner, whereas dexamethasone treatment had no effect on cell proliferation. Cotreatment with Sasa veitchii extract repressed all-trans-retinoic acid-induced toxicity in human embryonic palatal mesenchymal cells. We found that cotreatment with Sasa veitchii extract protected all-trans-retinoic acid-induced cyclin D1 downregulation in human embryonic palatal mesenchymal cells. Furthermore, Sasa veitchii extract suppressed all-trans-retinoic acid-induced miR-4680-3p expression. Additionally, the expression levels of the genes that function downstream of the target genes ( ERBB2 and JADE1 ) of miR-4680-3p in signaling pathways were enhanced by cotreatment with Sasa veitchii extract and all-trans-retinoic acid compared to all-trans-retinoic acid treatment. These results suggest that Sasa veitchii extract suppresses all-trans-retinoic acid-induced inhibition of cell proliferation via modulation of miR-4680-3p expression.

The Semaphorin 3A-AKT axis-mediated cell proliferation in salivary gland morphogenesis and adenoid cystic carcinoma pathogenesis.

We recently demonstrated that Semaphorin 3 A (Sema3A), the expression of which is negatively regulated by Wnt/ß-catenin signaling, promotes odontogenic epithelial cell proliferation, suggesting the involvement of Sema3A in tooth germ development. Salivary glands have a similar developmental process to tooth germ development, in which reciprocal interactions between the oral epithelium and adjacent mesenchyme proceeds via stimulation with several growth factors; however, the role of Sema3A in the development of salivary glands is unknown. There may thus be a common mechanism between epithelial morphogenesis and pathogenesis; however, the role of Sema3A in salivary gland tumors is also unclear. The current study investigated the involvement of Sema3A in submandibular gland (SMG) development and its expression in adenoid cystic carcinoma (ACC) specimens. Quantitative RT-PCR and immunohistochemical analyses revealed that Sema3A was expressed both in epithelium and in mesenchyme in the initial developmental stages of SMG and their expressions were decreased during the developmental processes. Loss-of-function experiments using an inhibitor revealed that Sema3A was required for AKT activation-mediated cellular growth and formation of cleft and bud in SMG rudiment culture. In addition, Wnt/ß-catenin signaling decreased the Sema3A expression in the rudiment culture. ACC arising from salivary glands frequently exhibits malignant potential. Immunohistochemical analyses of tissue specimens obtained from 10 ACC patients showed that Sema3A was hardly observed in non-tumor regions but was strongly expressed in tumor lesions, especially in myoepithelial neoplastic cells, at high frequencies where phosphorylated AKT expression was frequently detected. These results suggest that the Sema3A-AKT axis promotes cell growth, thereby contributing to morphogenesis and pathogenesis, at least in ACC, of salivary glands.

Factors Predicting Tongue Pressure Decline among Community-Dwelling Older Adults: The Takashimadaira Study.

A limited number of longitudinal studies have explored factors contributing to decreases in tongue pressure (TP). This longitudinal study aimed to clarify the factors affecting TP decline among community-dwelling older adults. We followed the Takashimadaira Study participants with a baseline TP ≥ 30 kPa for 2 years. A TP of <30 kPa at follow-up was defined as TP decline. We used Poisson regression with robust standard errors to explore the factors related to TP decline. The studied baseline variables were dental status, sociodemographic characteristics, health behaviors, appetite, medical conditions, physical function, cognitive status, and anthropometric and body composition characteristics. Inverse probability weighting (IPW) was used to adjust for selection bias. Overall, 357 individuals (159 men and 198 women) with a mean (standard deviation) age of 75.9 (4.1) years were included in the analyses. Of these, 59 study participants (16.5%) exhibited TP decline. After adjusting for baseline TP and applying IPW, poor appetite (incident rate ratio [95% confidence interval] = 1.58 [1.01−2.48]), low skeletal muscle mass index (1.66 [1.02−2.70]), and cognitive impairment (1.93 [1.12−3.33]) were associated with TP decline. In conclusion, we demonstrated that baseline appetite, body composition, and cognitive status could predict future TP decline among community-dwelling older adults.

Relationship between Chewing Ability and Nutritional Status in Japanese Older Adults: A Cross-Sectional Study.

OBJECTIVES: This study aimed to determine the relationship between objective chewing ability and the nutritional status of Japanese community-dwelling elders. DESIGN: A cross-sectional study. PARTICIPANTS: A total of 509 community-dwelling elders living in the Tokyo metropolitan area participated in a comprehensive survey conducted in October 2013. MEASUREMENTS: The basic characteristics were sex, age, and body mass index. Undernutrition was examined through serum albumin levels. Chewing ability was examined through color-changeable xylitol gum by evaluating the color changes in chewing gum. Nutritional intake was examined using the semi-quantitative food frequency questionnaire. RESULTS: In the poor chewing ability group, all nutrient intake levels were significantly low, except for carbohydrates, and intake levels for all food groups were significantly low, except for cereals, confectionery, sugars, seasonings, and spices. Additionally, after adjusting for covariates for sex, age, Tokyo Metropolitan Institute of Gerontology-Index of Competence (TMIG-IC) score, Mini-Mental State Examination (MMSE) score, body mass index (BMI), stroke, number of functional teeth, energy intake, and protein intake, chewing ability was found to be significantly associated with undernutrition. CONCLUSION: We concluded that chewing ability was closely associated with nutrient and different food groups' intake, as well as undernutrition, among Japanese community-dwelling elders. Thus, to ensure comprehensive nutritional management, nutritionists and dentists should collaborate when treating the same patients.

Oral frailty and gait performance in community-dwelling older adults: findings from the Takashimadaira study.

Purpose This cross-sectional study compared gait performance between community-dwelling older adults with and without accumulated deficits in oral health, defined as oral frailty.Methods A total of 1,082 individuals (439 men and 643 women; mean age, 77.1 years) from the Takashimadaira study were included in the current analysis. Based on a multifaceted oral health assessment, oral frailty was defined as having three or more of the following six components: (i) fewer teeth, (ii) low masticatory performance, (iii) low articulatory oral motor skills, (iv) low tongue pressure, (v) difficulties in eating, and (vi) swallowing. Eight gait parameters were assessed using an electronic walkway. Gait characteristics comparison between groups with and without oral frailty was performed using multiple linear regression models. Models were adjusted for age, sex, educational status, income, smoking, drinking, physical activity level, height, body mass index, comorbidities, and the presence of chronic pain.Results Oral frailty was observed in 227 (21.0%) participants. After adjusting for potential confounders, the participants with oral frailty had slower gait speed, shorter stride and step length, wider step width, and longer double support duration as well as higher variability of stride length and step length.Conclusions Oral frailty was associated with poor gait performance among community-dwelling older adults.

Association between decrease in frequency of going out and oral function in older adults living in major urban areas.

AIM: To examine the association between a decrease in the frequency of going out and oral function in independent older adults living in the urban area of Tokyo. METHODS: The participants analyzed were 785 older adults from the "Takashimadaira Study" (344 men and 441 women, age 77.0 ± 4.6 years). This study investigated the following items: decrease in frequency of going out; basic characteristics (sex, age); physical factors, such as oral function (difficulty chewing, difficulty swallowing, dry mouth); body pain; the Japan Science and Technology Agency Index of Competence; physical activities; psychological factors, such as the Geriatric Depression Scale-15 score; and social and environmental factors, such as the presence or absence of participation in organization activities. RESULTS: To investigate the factors associated with a decrease in frequency of going out, logistic regression analysis showed an association with age (OR 1.08, 95% CI 1.03-1.13), difficulty chewing (OR 2.41, 95% CI 1.52-3.83), dry mouth (OR 1.68, 95% CI 1.07-2.64), body pain (OR 1.78, 95% CI 1.14-2.78), Japan Science and Technology Agency Index of Competence scores (OR 0.91, 95% CI 0.84-0.99), physical activities (OR 0.99, 95% CI 0.98-1.00), Geriatric Depression Scale-15 scores (OR 1.13, 95% CI 1.05-1.21) and organization activities (OR 1.94, 95% CI 1.22-3.07). Covariance structural analyses showed that both "difficulty chewing" and "dry mouth" significantly affected "decrease in frequency of going out." In addition, decrease in frequency of going out was significantly affected by " Geriatric Depression Scale-15 scores" through oral function. CONCLUSIONS: The relationship between oral function and decrease in frequency of going out was clarified, after the multifaceted factors were adjusted. Geriatr Gerontol Int 2019; 19: 792-797.

Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) expression and possible function in mouse tooth germ development.

Abnormal expression of Facioscapulohumeral muscular dystrophy (FSHD) region gene 1 (FRG1) is involved in the pathogenesis of FSHD. FRG1 is also important for the normal muscular and vascular development. Our previous study showed that FRG1 is one of the highly expressed genes in the mandible on embryonic day 10.5 (E10.5) than on E12.0. In this study, we investigated the temporospatial expression pattern of FRG1 mRNA and protein during the development of the mouse lower first molar, and also evaluated the subcellular localization of the FRG1 protein in mouse dental epithelial (mDE6) cells. The FRG1 expression was identified in the dental epithelial and mesenchymal cells at the initiation and bud stages. It was detected in the inner enamel epithelium at the cap and early bell stages. At the late bell and root formation stages, these signals were detected in ameloblasts and odontoblasts during the formation of enamel and dentin matrices, respectively. The FRG1 protein was localized in the cytoplasm in the mouse tooth germ in vivo, while FRG1 was detected predominantly in the nucleus and faintly in the cytoplasm in mDE6 cells in vitro. In mDE6 cells treated with bone morphogenetic protein 4 (BMP4), the protein expression of FRG1 increased in cytoplasm, suggesting that FRG1 may translocate to the cytoplasm. These findings suggest that FRG1 is involved in the morphogenesis of the tooth germ, as well as in the formation of enamel and dentin matrices and that FRG1 may play a role in the odontogenesis in the mouse following BMP4 stimulation.

Thymosin beta 4 is associated with RUNX2 expression through the Smad and Akt signaling pathways in mouse dental epithelial cells.

In previous studies by our group, we reported that thymosin beta 4 (Tb4) is closely associated with the initiation and development of the tooth germ, and can induce the expression of runt-related transcription factor 2 (RUNX2) during the development of the tooth germ. RUNX2 regulates the expression of odontogenesis-related genes, such as amelogenin, X-linked (Amelx), ameloblastin (Ambn) and enamelin (Enam), as well as the differentiation of osteoblasts during bone formation. However, the mechanisms through which Tb4 induces the expression of RUNX2 remain unknown. In the present study, we employed a mouse dental epithelial cell line, mDE6, with the aim to elucidate these mechanisms. The mDE6 cells expressed odontogenesis-related genes, such as Runx2, Amelx, Ambn and Enam, and formed calcified matrices upon the induction of calcification, thus showing characteristics of odontogenic epithelial cells. The expression of odontogenesis-related genes, and the calcification of the mDE6 cells were reduced by the inhibition of phosphorylated Smad1/5 (p-Smad1/5) and phosphorylated Akt (p-Akt) proteins. Furthermore, we used siRNA against Tb4 to determine whether RUNX2 expression and calcification are associated with Tb4 expression in the mDE6 cells. The protein expression of p-Smad1/5 and p-Akt in the mDE6 cells was reduced by treatment with Tb4-siRNA. These results suggest that Tb4 is associated with RUNX2 expression through the Smad and PI3K-Akt signaling pathways, and with calcification through RUNX2 expression in the mDE6 cells. This study provides putative information concerning the signaling pathway through which Tb4 induces RUNX2 expression, which may help to understand the regulation of tooth development and tooth regeneration.