Silk-protein-based gradient hydrogels with multimode reprogrammable shape changes for biointegrated devices.

Biocompatible and morphable hydrogels capable of multimode reprogrammable, and adaptive shape changes are potentially useful for diverse biomedical applications. However, existing morphable systems often rely on complicated structural designs involving cumbersome and energy-intensive fabrication processes. Here, we report a simple electric-field-activated protein network migration strategy to reversibly program silk-protein hydrogels with controllable and reprogrammable complex shape transformations. The application of a low electric field enables the convergence of net negatively charged protein cross-linking networks toward the anode (isoelectric point plane) due to the pH gradient generated in the process, facilitating the formation of a gradient network structure and systems suitable for three-dimensional shape change. These tunable protein networks can be reprogrammed or permanently fixed by control of the polymorphic transitions. We show that these morphing hydrogels are capable of conformally interfacing with biological tissues by programming the shape changes and a bimorph structure consisting of aligned carbon nanotube multilayers and the silk hydrogels was assembled to illustrate utility as an implantable bioelectronic device for localized low-voltage electrical stimulation of the sciatic nerve in a rabbit.

In vivo biological safety investigation of Yb-CALGO femtosecond laser dental surgery.

While lasers have found their successful applications in various clinical specialties, in clinical dental practice, traditional mechanical drills are still predominantly utilized. Although erbium-doped lasers have been demonstrated for dental therapy, their clinical performance is still not satisfactory due to the long pulse width, low peak power, and small repetition rate. To attain a smaller thermal diffusion thus better biological safety and surgical precision, as well as more rapid ablation, the advancement of femtosecond laser techniques has opened another route of dental surgery; however, no biological safety investigation has been reported. Here, we present a systematic study of dental ablation by a Yb:CaAlGdO4 regenerative amplifier with a central wavelength of 1040 nm and pulse width of 160 fs. The in vivo experiment of dental surgery investigating the inflammatory response has been reported, for the first time to the best of our knowledge. It is demonstrated that dental surgery by Yb:CaAlGdO4 femtosecond laser ablation has better biological safety compared to the turbine drilling, thanks to its non-contact and ultrafast heat dissipation nature.

Polystyrene nanoplastics with different functional groups and charges have different impacts on type 2 diabetes.

BACKGROUND: Increasing attention is being paid to the environmental and health impacts of nanoplastics (NPs) pollution. Exposure to nanoplastics (NPs) with different charges and functional groups may have different adverse effects after ingestion by organisms, yet the potential ramifications on mammalian blood glucose levels, and the risk of diabetes remain unexplored. RESULTS: Mice were exposed to PS-NPs/COOH/NH2 at a dose of 5 mg/kg/day for nine weeks, either alone or in a T2DM model. The findings demonstrated that exposure to PS-NPs modified by different functional groups caused a notable rise in fasting blood glucose (FBG) levels, glucose intolerance, and insulin resistance in a mouse model of T2DM. Exposure to PS-NPs-NH2 alone can also lead the above effects to a certain degree. PS-NPs exposure could induce glycogen accumulation and hepatocellular edema, as well as injury to the pancreas. Comparing the effect of different functional groups or charges on T2DM, the PS-NPs-NH2 group exhibited the most significant FBG elevation, glycogen accumulation, and insulin resistance. The phosphorylation of AKT and FoxO1 was found to be inhibited by PS-NPs exposure. Treatment with SC79, the selective AKT activator was shown to effectively rescue this process and attenuate T2DM like lesions. CONCLUSIONS: Exposure to PS-NPs with different functional groups (charges) induced T2DM-like lesions. Amino-modified PS-NPs cause more serious T2DM-like lesions than pristine PS-NPs or carboxyl functionalized PS-NPs. The underlying mechanisms involved the inhibition of P-AKT/P-FoxO1. This study highlights the potential risk of NPs pollution on T2DM, and provides a new perspective for evaluating the impact of plastics aging.

Nell-1 promotes the neural-like differentiation of dental pulp cells.

Previous studies showed that Nel-like molecule-1 (Nell-1) can positively regulate odontoblastic differentiation and dentin formation. Intriguingly, our group found that Nell-1 is co-expressed with neural markers. The purpose of this study was to investigate whether Nell-1 protein plays a regulatory role in the differentiation of dental pulp cells into neural-like cells by in vivo and in vitro studies. The expression patterns of Nell-1 and dental pulp neural markers were observed by double immunofluorescence staining in normal dental pulp tissue sections of Wistar rat. Collagen sponge containing Nell-1 protein was added into the pulp cavity of rat molars in order to observe the expression patterns of neural markers in rat dental pulp repair and regeneration model by immunohistochemical staining. Moreover, human dental pulp stem cells (hDPSCs) were cultured, and different concentrations of Nell-1 protein were added for 12 h, 24 h, and 72h. The expression of neural markers was detected by using quantitative real-time polymerase chain reaction and Western blot. Nell-1 was co-expressed with neural markers including substance P (SP) and Nestin in rat dental pulp tissue. The expression of neural markers including SP, neuron-specific enolase (NSE), and Nestin was increased obviously in rat dental pulp tissues stimulated with Nell-1 protein. In cultured hDPSCs induced by Nell-1 protein, the expression of neural markers including glial fibrillary acidic protein (GFAP), Nestin, and ß-III tubulin was increased. Nell-1 plays a positive role in inducing the differentiation of DPSCs into neural-like cells.

Interaction of Nel-like molecule 1 with apoptosis related protein 3 with its influence on human dental pulp cells proliferation and differentiation into odontoblasts.

Nel-like molecule 1 (Nell-1) is an essential positive regulator of tooth development and odontoblast differentiation. However, its precise mechanism remains undetermined. This study aims to explore the possible receptor or binding protein of Nell-1. Results showed that Nell-1 and Apoptosis related protein 3(APR3) expression levels were high in odontoblasts and inversely correlated. Endogenous Nell-1 co-immunoprecipitated with APR3, and this co-IP was reciprocal. Double immunofluorescence staining revealed that Nell-1 and APR3 colocalized on the nuclear envelope of human dental pulp cells. Nell-1 inhibited the proliferation of these cells co-infected with APR3 through Cyclin D1 downregulation. The interaction of Nell-1 with APR3 stimulated alkaline phosphatase (ALP) activity and promoted the expression and mineralization of DSPP, ALP, OPN, and BSP. The shRNA of APR3 decreased cell differentiation and mineralization. Nell-1 could reciprocally interact with APR3 and stimulate the differentiation and mineralization of human dental pulp cells. Future studies should explore the potential functional connection and the molar mechanism of such interaction.

Effect of Antimicrobial Denture Base Resin on Multi-Species Biofilm Formation.

Our aims of the research were to study the antimicrobial effect of dimethylaminododecyl methacrylate (DMADDM) modified denture base resin on multi-species biofilms and the biocompatibility of this modified dental material. Candida albicans (C. albicans), Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), as well as Actinomyces naeslundii (A. naeslundii) were used for biofilm formation on denture base resin. Colony forming unit (CFU) counts, microbial viability staining, and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) array were used to evaluate the antimicrobial effect of DMADDM. C. albicans staining and Real-time PCR were used to analyze the morphology and expression of virulence genes of C. albicans in biofilm. Lactate dehydrogenase (LDH) array and Real-time PCR were conducted to examine the results after biofilm co-cultured with epithelial cell. Hematoxylin and eosin (HE) staining followed by histological evaluation were used to study the biocompatibility of this modified material. We found that DMADDM containing groups reduced both biomass and metabolic activity of the biofilm significantly. DMADDM can also inhibit the virulence of C. albicans by means of inhibiting the hyphal development and downregulation of two virulence related genes. DMADDM significantly reduced the cell damage caused by multi-species biofilm according to the LDH activity and reduced the expression of IL-18 gene of the cells simultaneously. The in vivo histological evaluation proved that the addition of DMADDM less than 6.6% in denture material did not increase the inflammatory response (p > 0.05). Therefore, we proposed that the novel denture base resin containing DMADDM may be considered as a new promising therapeutic system against problems caused by microbes on denture base such as denture stomatitis.

Oral lichen planus may enhance the expression of Th17-associated cytokines in local lesions of chronic periodontitis.

OBJECTIVES: This study aims to compare the expression levels of interleukin (IL)-17 and IL-23 in local periodontal tissues from patients with both chronic periodontitis and oral lichen planus (CP-OLP), patients with chronic periodontitis (CP) only, patients with oral lichen planus (OLP) only, and healthy controls (HC). MATERIALS AND METHODS: The periodontal tissues were collected from 15 CP-OLP patients, 15 CP patients, 15 OLP patients, and 10 healthy controls. Immunohistochemistry (IHC) and real-time quantitative PCR (qPCR) was performed to investigate the protein and mRNA expression level of IL-17 and IL-23 in periodontal lesions from these four groups. RESULTS: IHC statistical analysis showed that the expression level of IL-17- and IL-23p19-positive cells significantly increased in CP-OLP group compared with that in CP (P < 0.01) and OLP groups (P < 0.05), showing intense staining reaction in local lamina propria lesions. Meanwhile, qPCR result showed higher IL-17 mRNA level in CP-OLP compared with that in CP and OLP groups and demonstrated a significant increase than OLP group (P < 0.05). Moreover, it was found that IL-17 mRNA expression level in erosive CP-OLP patients was significantly correlated with probing depth and attachment loss (P < 0.05). CONCLUSIONS: This study indicated that there was an increased expression level of IL-17 and IL-23 in periodontal tissues from periodontitis patients with oral lichen planus, which might aggravate the inflammatory response in local lesions. CLINICAL RELEVANCE: Oral lichen planus and chronic periodontitis may have interaction in disease pathogenesis, while IL-17 detection in local lesions may be helpful in identifying the disease severity in periodontitis patients with oral lichen planus.

Efficacy of a novel dentifrice containing bioactive glass-ceramic for dentinal hypersensitivity: A double-blind randomized controlled trial in Chinese adults.

OBJECTIVE: To assess the efficacy and safety of a toothpaste containing 7.5 % HX-BGC in combating dentinal hypersensitivity. METHODS: A single-center, randomized, double-blind, three-group parallel-controlled design was employed, with Schiff Index and Yeaple Index as measurement indicators. The study evaluated the effectiveness of HX-BGC toothpaste, NovaMin toothpaste, and a negative control toothpaste without desensitizing agents. Eligible subjects underwent baseline examination after a 2-week washout period, and those meeting inclusion criteria and not meeting exclusion criteria entered the study. Participants were randomly assigned to use one of the three toothpastes. Follow-up examinations were conducted immediately after a single use and at 2, 4, and 6 weeks. Intra-group and inter-group comparisons were made for Schiff and Yeaple indices. Safety of the experimental toothpastes was assessed through participant feedbacks and oral soft tissue examinations. RESULTS: Subjects in the three groups were balanced in terms of age and gender distribution, with no baseline differences in indicators. Immediately after a single application of toothpaste, Yeaple indices increased, and Schiff indices decreased, with no significant differences among the groups. After 2 weeks of continuous use, Yeaple indices increased in all groups, with significant differences observed between the HX-BGC group and the other two groups. Schiff indices decreased in all groups, with the NovaMin group showing significant differences compared to the negative control group. At weeks 4 and 6, both indices in the HX-BGC group and the NovaMin group were significantly better than those in the negative control group, with the HX-BGC group outperforming the NovaMin group in the Yeaple index. No serious adverse reactions related to the study products were observed or reported by any participants. CLINICAL SIGNIFICANCE: This clinical trial confirmed the efficacy of HX-BGC in anti-dentinal hypersensitivity and supported the clinical application of the dentifrice containing HX-BGC. CONCLUSION: Compared to the negative control group, both HX-BGC and NovaMin toothpaste groups demonstrated more significant effects in combating dentinal hypersensitivity. No adverse reactions related to the experimental toothpastes were observed.

Comparing the effects and mechanisms of exposure to polystyrene nanoplastics with different functional groups on the male reproductive system.

After aging in the environment, some nanoplastics will carry different charges and functional groups, thereby altering their toxicological effects. To evaluate the potential impact of aging of nanoplastics on the mammalian reproductive system, we exposed C57BL/6 male mice to a dose of 5 mg/kg/d polystyrene nanoparticles (PS-NPs) with different functional groups (unmodified, carboxyl functionalized and amino functionalized) for 45 days for this study. The results suggest that PS-NPs with different functional groups triggered oxidative stress, a decreased in the testis index, disruption of the outer wall of the seminiferous tubules, reduction in the number of spermatogonia cells and sperm counts, and an increased in sperm malformations. We performed GO and KEGG enrichment analysis on the differentially expressed proteins, and found they were mainly enriched in protein transport, RNA splicing and mTOR signaling. We confirmed that the PI3K-AKT-mTOR pathway is over activated, which may lead to reduction of spermatogonia stem cells by over differentiation. Strikingly, PS-NPs with functional group modifications are more toxic than those of unmodified polystyrene, and that PS-NPs with positively charged amino modifications are the most toxic. This study provides a new understanding for correctly evaluating the toxicological effects of plastic aging, and of the mechanism responsible for the reproductive toxicity caused by nanoplastics.

Lacticaseibacillus rhamnosus inhibits the development of dental caries in rat caries model and in vitro.

OBJECTIVES: Dental caries result from a microbial imbalance in the oral cavity. Probiotics ecologically modulate the oral microflora to prevent caries. This study evaluated the anti-cariogenic effects of two Lacticaseibacillus rhamnosus strains in vitro and in vivo to provide a more theoretical basis for its clinical applications in caries prevention. METHODS: In the study, cariogenic biofilms were grown with L. rhamnosus (LGG) or L. rhamnosus ATCC 7469 and analyzed. Quantitative real-time PCR (qPCR), Scanning Electron Microscope (SEM), and Confocal laser scanning microscope (CLSM) were used to detect the changes in the composition and architectures; cariogenic activity was measured by the lactic acid production and Transverse Microradiography (TMR). The effects of LGG on the 12 Sprague-Dawley rat caries model were assessed using Keyes scores and micro-CT analysis. Oral microbiome changes were evaluated through 16S rRNA gene high-throughput sequencing. RESULTS: L. rhamnosus can reduce cariogenic bacteria in biofilm by 14.7 % to 48.9 %, with LGG exhibiting more potent inhibitory effects. Both strains of L. rhamnosus can adhere to the surface of biofilms, reduce the extracellular polysaccharides (EPS) matrix, and loosen the biofilm structure. L. rhamnosus inhibited cariogenic activity by reducing the lactic acid production in biofilms. The bovine enamel blocks presented lower mineral loss values and lesion depth values in the group Core+L.rh and Core+LGG. LGG-ingested rats had significantly lower levels of moderate dentin lesions and higher mineral density than the control group. The 16 s rRNA gene sequencing revealed that LGG regulated the beta diversity of the oral microbial community in the rat dental caries model. CONCLUSIONS: This study revealed the promising potential of L. rhamnosus, especially the LGG strain, in the ecological prevention of dental caries. CLINICAL SIGNIFICANCE: Probiotics may provide a strategy for preventing caries by regulating the oral microecological balance. The study revealed the promising anti-caries potential of the LGG probiotic strain in vivo and in vitro. It is expected that LGG could be used as an oral probiotic for the clinical prevention and treatment of caries.

Associations of tooth loss with risk of all-cause and cause-specific mortality among US adults with diabetes mellitus.

OBJECTIVES: To determine whether tooth loss affects all-cause and cause-specific mortality in a nationally representative sample of adults with diabetes mellitus (DM) in the United States. METHODS: This prospective cohort study involved 8207 participants aged 30 years or older at baseline, all diagnosed with diabetes mellitus and enrolled in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Tooth loss was stratified into 28 teeth (complete), 20-27 teeth (tooth loss), 9-19 teeth (lacking functional), 1-8 teeth (severe tooth loss) and edentulism. To estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for all-cause and specific-cause mortality in diabetes mellitus participants according to tooth loss, multivariate cox proportional hazards regression models were used. Relationships between mortality and quartiles of mean tooth loss levels were analyzed, with the lowest quartile as the baseline for comparisons. RESULTS: During a median of 6.92 years of follow-up, 2317 deaths were documented. After multivariate adjustments, higher tooth loss levels were significantly and non-linearly associated with higher risks of all-cause, CVD-related and DM-related mortality among participants with DM. When compared with the reference group of mean tooth loss levels, the highest quartile showed significantly increased risks: all-cause mortality (HR, 2.11; 95 % CI, 1.53-2.91, P-trend < 0.001), CVD-related mortality (HR, 3.24, 95 % CI, 1.54-6.85, P-trend < 0.001) and DM-related mortality (HR, 2.78, 95 % CI, 1.15-6.68, P-trend < 0.001). CONCLUSIONS: Tooth loss is associated with an increased risk of all-cause, CVD-related and diabetes mellitus mortality among adults with diabetes mellitus in the US. CLINICAL SIGNIFICANCE: This study presents evidence for physicians and dentists that higher tooth loss was significantly associated with increased risk of all-cause, CVD-related and diabetes mellitus mortality in a dose-response manner among adults with diabetes mellitus. Therefore, assessment of survival in individuals with diabetes mellitus could pay attention to the tooth loss.

The remineralization effect of GERM CLEAN on early human enamel caries lesions in vitro.

This study aimed to evaluate the remineralization effect of GERM CLEAN, a novel antibacterial peptide, on early enamel caries. Thirty human enamel blocks from thirty teeth were randomly divided into three groups: double distilled water (DDW group), GERM CLEAN (GC group), and 1000 ppm fluoride (NaF group). Specimens were demineralized for 3 days (pH 4.6) followed by pH cycling twice daily for 14 days. For a pH cycle, specimens received corresponding treatments for 5 min, then were immersed in demineralizing solution for 1 h, received corresponding treatments again, and finally were immersed in remineralizing solution (pH 7.0) for approximately 11 h. Specimens were washed with DDW after each treatment. Microindentation tests, atomic force microscopy (AFM), and transverse micro-radiography (TMR) were conducted to analyze enamel blocks. GC demonstrated a lower percentage of surface microhardness recovery (SMHR%) (p < 0.0001), rougher surfaces (p < 0.0001), deeper lesion depth (p = 0.001), and more mineral loss (p = 0.001) than NaF, but showed higher SMHR% (p < 0.0001), smoother surfaces (p < 0.0001), shallower lesion depth (p = 0.049), and less mineral loss (p = 0.001) than DDW. As a result, GERM CLEAN has the potential to promote the remineralization of demineralized enamel.

Extraskeletal myxoid chondrosarcoma of the gingival: a rare case report and review of the literature.

BACKGROUND: Extraskeletal myxoid chondrosarcoma (EMC) is a rare malignant tumor described in the head and neck region, especially in the gingival. We present one case arising in the gingival of right mandible, and briefly reviewed the related literature. CASE PRESENTATION: A 24-year-old male patient with a lesion of 3.5*2.0 cm in buccal gingival of right posterior mandible for 2 months. The tumor was composed of cartilaginous structures and myxoid matrix. Immunohistochemical(IHC) showed that the tumor cells to be positive for vimentin, focally positive for S-100, negative for calponin, SMA, SOX10. The Ki-67 labelling index was 80%. Fluorescent in situ Hybridization (FISH) was positive for NR4A3 rearrangement. CONCLUSIONS: Due to its unusual site and low incidence in the oral region, a combination of histological findings, immunohistochemistry, and molecular pathology as well as differential diagnosis with other diseases should be taken into consideration in the process of clinical diagnosis and treatment.

Efficacy of a toothpaste containing paeonol, potassium nitrate, and strontium chloride on dentine hypersensitivity: A double-blind randomized controlled trial in Chinese adults.

Objective: The purpose of this randomized controlled trial was to compare the efficacy of a toothpaste containing paeonol, potassium nitrate, and strontium chloride with control toothpaste on dentine hypersensitivity (DH). Methods: DH patients who had at least two sensitive teeth and did not use desensitization toothpaste in the past 3 months were randomly allocated to either test or control group. The toothpaste containing paeonol, potassium nitrate, and strontium chloride was used in the test group, while the placebo toothpaste used in control group. The outcome measures included Yeaple probe score and Schiff Index score at 4 and 8 weeks. The patients, personnel and assessors were blinded to the allocation. The differences in Yeaple probe score and Schiff Index score between groups were analyzed with ANOVA. Results: 91 eligible subjects were randomized. 88 of them completed 8-week follow-up and were analyzed (45 in the test group and 43 in the control group). In both groups, the Yeaple probe score showed an upward trend, while the Schiff sensitivity score showed a downward trend. At week 8, the Yeaple probe score had increased by 30.22 g in the test group, and the Schiff Index score had decreased by 0.89. Compared with the control group, the Yeaple probe score in the test group increased by 286.85% from baseline, and the Schiff Index score decreased by 42.96%, showing a statistically significant difference. Five cases of adverse events were observed. Conclusion: The toothpaste containing paeonol, potassium nitrate, and strontium chloride was effective against DH. Clinical significance: This combination of paeonol, potassium nitrate and strontium chloride could be a novel functional ingredient choice for anti-hypersensitivity products in future. Registration: The trial was registered in the Chinese Clinical Trial Registry (ChiCTR2000041417).

The effect and a mechanistic evaluation of polystyrene nanoplastics on a mouse model of type 2 diabetes.

Nanoplastics have become ubiquitous in the global environment and have attracted increasing attention. However, whether there is an influence between exposure to nanoplastics and diabetes is unclear. To determine the effects of exposure to Polystyrene nanoplastics (PS-NPs) and evaluate the underlying mechanisms, mice were orally exposed to PS-NPs at dosages of 1, 10, 30 mg/kg/day for 8 weeks, alone or combined with a high fat diet and streptozocin (STZ) injection. Our data showed that exposure to 30 mg/kg/day PS-NPs alone induced a significant increase in blood glucose, glucose intolerance and insulin resistance. Combined with a high fat diet and STZ injection, PS-NPs exposure markedly aggravated oxidative stress, glucose intolerance, insulin tolerance and insulin resistance, and induced lesions in the liver and pancreas. PS-NPs exposure could decrease the phosphorylation of AKT and GSK3ß, and treatment with SC79, a selective AKT activator, could increase the level of AKT and GSK3ß phosphorylation, effectively alleviating the increase in ROS levels in the liver or pancreas, and slightly attenuating the increase in fasting blood glucose levels and insulin resistance induced by PS-NPs exposure. This showed that exposure to PS-NPs aggravated type 2 diabetes and the underlying mechanism partly involved in the inhibition of AKT/GSK3ß phosphorylation.

A new insight into the low membrane fouling tendency of liquid-liquid hollow fiber membrane contactor capturing ammonia from human urine.

To unravel the low membrane fouling tendency and underlying membrane fouling mechanism of liquid-liquid hollow fiber membrane contactor (LL-HFMC) capturing ammonia from human urine, the ammonia flux decline trend, membrane fouling propensity, foulant-membrane thermodynamic interaction energy and microscale force analysis at different feed urine pH were comprehensively investigated. The 21-d continuous experiments showed that the ammonia flux decline trend and membrane fouling propensity significantly strengthened with the decrease of feed urine pH. The calculated foulant-membrane thermodynamic interaction energy decreased with the decreasing feed urine pH and agreed with the ammonia flux decline trend and membrane fouling propensity. The microscale force analysis showed that the absence of hydrodynamic water permeate drag force resulted in the foulant located at long distance from the membrane were difficult to approach the membrane surface, thus considerably alleviating membrane fouling. Additionally, the vital thermodynamic attractive force near the membrane surface increased with the decrease of feed urine pH, which made the membrane fouling further relieved at high pH condition. Therefore, the absence of water permeate drag force and operating at high pH condition minimized the membrane fouling during the LL-HFMC ammonia capture process. The obtained results provide a new insight into the low membrane tendency mechanism of LL-HFMC.

Smurf1 regulates ameloblast polarization by ubiquitination-mediated degradation of RhoA.

Cell polarity is essential for ameloblast differentiation and enamel formation. Smurf1 can mediate cell polarization through ubiquitination degradation of specific substrates. But it remains unclear whether Smurf1 could regulate ameloblast polarity and the underlying mechanism. Here, immuno-fluorescence staining and RT-qPCR were applied to detect the expression of Smurf1 and F-actin. A mouse lower incisor defect model was constructed. Scanning electron microscope, rat lower incisor culture, western blot, wound healing assay and trans-well migration assay were performed to detect the influence of Smurf1 knockdown on ameloblast. IF double staining, western blot and co-immunoprecipitation were conducted to detect the interaction between Smurf1 and RhoA. The in vivo experiment was also performed. We found that Smurf1 was mainly expressed in the membrane and cell cortex of ameloblast, similar to F-actin. Smurf1 expression increased along ameloblast polarization and differentiation. After knocking down Smurf1, the cytoskeleton and cell morphology changed and the cell polarity was damaged. Smurf1 regulated ameloblast polarity through ubiquitination degradation of activated RhoA in vitro. Local knockdown of Smurf1 in rat lower incisor ameloblast resulted in ameloblast polarity loss, enamel matrix secretion disorder and chalky enamel, but RhoA inhibitor Y-27632 could reverse this effect. Collectively, Smurf1 could regulate the polarization of ameloblast through ubiquitination degradation of activated RhoA, which contributed to the knowledge of tooth development and provided new research ideas for cell polarity.

The effect of argon cold atmospheric plasma on the metabolism and demineralization of oral plaque biofilms.

Objective: The aim of this study was to design and optimize a cold atmospheric plasma (CAP) device that could be applied in an oral environment and to study its effects on plaque biofilm metabolism and regrowth, as well as microbial flora composition and enamel demineralization. Method: CAP was obtained through a dielectric barrier discharge device; the optical properties were analyzed using emission spectroscopy. The electrochemical analysis of plasma devices includes voltametric characteristic curves and Lissajous. The Streptococcus mutans (UA159) and saliva biofilms were treated in vitro, and the effects of CAP on biofilm metabolism were investigated using MTT and lactate dehydrogenase assays. The duration of antibacterial activity on biofilms was examined, scanning electron microscopy was used to observe the morphology of biofilms, and 16S rRNA sequencing was used to explore the influence of CAP on the microbial flora composition of saliva biofilms. An in vitro model of biofilm-enamel demineralization was designed, and the effect of CAP on enamel demineralization was evaluated by micro surface hardness and micro-CT analysis. Results: CAP had antibacterial proliferative ability toward Streptococcus mutans biofilms and saliva biofilms and was stronger than ultraviolet under the same tested conditions. After 24 h, the antibacterial effect disappeared, which proved the short-term timeliness of its bactericidal ability. CAP can inhibit the acid production of biofilms, and its inhibitory effect on saliva biofilms can be extended to 24 h. CAP had a strong ability to regulate the composition of plaque biofilms, especially for Lactococcus proliferation, a major acid-producing bacterium in microcosm biofilms. The CAP-treated enamels were more acid-tolerant than non-treated controls. Conclusion: CAP had an explicit bactericidal effect on caries-related biofilms, which is a short-term antibacterial effect. It can inhibit the acid production of biofilms and has a downregulation effect on Lactococcus in saliva biofilms. CAP can help reduce demineralization of enamel.

Co-exposure to polystyrene microplastics and di-(2-ethylhexyl) phthalate aggravates allergic asthma through the TRPA1-p38 MAPK pathway.

Increasing attention has been paid to the potential impact of microplastics (MPs) pollution on human health. MPs and phthalates coexist in the environment, however, the effects of exposure to MPs alone or to a combination of di-(2-ethylhexyl) phthalate (DEHP) and MPs on allergic asthma are unclear. This study investigates the effects of exposure to polystyrene microplastics (PS-MPs) or co-exposure with DEHP, on allergic asthma, and the underlying molecular mechanisms. We established an allergic asthma model using ovalbumin, and mice were exposed to PS-MPs (5 mg/kg bw/day) alone, or combined with DEHP (0.5, 5 mg/kg bw/day), for 28 days. The results showed that in the presence of ovalbumin (OVA) sensitization, exposure to PS-MPs alone slightly affected airway inflammation, and airway hyperresponsiveness, while co-exposure to PS-MPs and DEHP caused more significant damage. Co-exposure also induced more oxidative stress and Th2 immune responses, and activation of the TRPA1 and p38 MAPK pathways. The aggravation of asthmatic symptoms induced by co-exposure to PS-MPs and DEHP were inhibited by blocking TRPA1 ion channel or p38 MAPK pathway. The results demonstrated that co-exposure to PS-MPs and DEHP exacerbates allergic asthma, by exacerbating oxidative stress and inflammatory responses, and activating the TRPA1-p38 MAPK pathway.