Epithelial Bone Morphogenic Protein 2 and 4 Are Indispensable for Tooth Development.

The Bmp2 and Bmp4 expressed in root mesenchyme were essential for the patterning and cellular differentiation of tooth root. The role of the epithelium-derived Bmps in tooth root development, however, had not been reported. In this study, we found that the double abrogation of Bmp2 and Bmp4 from mouse epithelium caused short root anomaly (SRA). The K14-cre;Bmp2 f/f ;Bmp4 f/f mice exhibited a persistent Hertwig's Epithelial Root Sheath (HERS) with the reduced cell death, and the down-regulated BMP-Smad4 and Erk signaling pathways. Moreover, the Shh expression in the HERS, the Shh-Gli1 signaling, and Nfic expression in the root mesenchyme of the K14-cre;Bmp2 f/f ;Bmp4 f/f mice were also decreased, indicating a disrupted epithelium- mesenchyme interaction between HERS and root mesenchyme. Such disruption suppressed the Osx and Dspp expression in the root mesenchyme, indicating an impairment on the differentiation and maturation of root odontoblasts. The impaired differentiation and maturation of root odontoblasts could be rescued partially by transgenic Dspp. Therefore, although required in a low dosage and with a functional redundancy, the epithelial Bmp2 and Bmp4 were indispensable for the HERS degeneration, as well as the differentiation and maturation of root mesenchyme.

Photothermal treatment of oropharyngeal cancer with carbon-defective silicon carbide.

Oral squamous carcinoma (OSCC) is a clinical common tumor with high recurrence rate and low 5 year survival rate. In this work, photothermal antitumor treatment has been performed to treat OSCC by taking anti-wound infection into consideration. By introducing C defects, we have successfully converted the semi-conductive SiC into metallic carbon-defective silicon carbide (SiC1-x), and endowed it with the near infrared absorption property for photothermal therapy (PTT). The results revealed that SiC1-x mediated PTT treatment could remove solid OSCC tumor in a biosafe way, showing low hematotoxicity, cytotoxicity and tissue toxicity. Moreover, the low invasion of PTT treatment could not only prevent the invasion of bacteria, but also realize an antibacterial effect on the wound, both of which are important for oral surgery. SiC1-x could be excreted from the body post treatment, which thus reduces the long-term potential toxicity. On the whole, this study provided a promising way to treat OSCC in an effective and safe way.

Low doses of deoxynivalenol inhibit the cell migration mediated by H3K27me3-targeted downregulation of TEM8 expression.

Deoxynivalenol (DON) is a mycotoxin produced by multipleFusariumspecies that often contaminates cereals and threatens human and animal health. A wide range of cytotoxic effects, such as the induction of DNA damage, an increase in mitochondrial permeability and the inhibition of macromolecule synthesis, have been reported. However, the effects of DON on cell migration-a fundamental process in living cells critical for normal development, immune responses, and disease processes-and the mechanism underlying these effects are still unclear. Here, we showed that DONsignificantly inhibited the migration of MRC-5, CCD-18Co, HCT116 and WM793 cells at 50 ng/ml, 50 ng/ml, 400 ng/ml and 250 ng/ml, respectively, which maintained cell viability at 90%. Further analysis showed that DON inhibited the expression of tumour endothelial marker 8 (TEM8), a key gene in cell migration. Furthermore, we showed that DON inhibited the expression of TEM8 through increasing the level of H3K27me3 in the TEM8 promoter. Finally, overexpression of TEM8 or treating by H3K27me3-specific inhibitor GSK126 attenuated the inhibitory effect of DON on cell migration. In summary, low doses of DON at approximately dietary exposure significantly inhibited cell migration by downregulating the expression of TEM8 in a manner mediated by H3K27me3, which may generate increasing concerns for the risk of DON exposure.

Lactobacillus rhamnosus GG supplementation modulates the gut microbiota to promote butyrate production, protecting against deoxynivalenol exposure in nude mice.

Deoxynivalenol (DON) is the most common mycotoxin in grains, and DON exposure causes gastrointestinal inflammation and systemic immunosuppression. The immunosuppression caused by DON has raised serious concerns about whether it is safe to use probiotics in immunocompromised hosts. Gut microbiota remodeling by Lactobacillus is a potential effective strategy to prevent DON exposure. The athymic nude mice were chose as the model of immunocompromised animals. We tested the effect of the probiotic Lactobacillus rhamnosus GG (LGG) or Lactobacillus acidophilus (LA) supplementation on host protection against DON exposure and the underlying mechanisms in nude mice. DON exposure induced endoplasmic reticulum (ER) stress and impaired intestinal barrier function and microbiota, which were relieved by LGG supplementation but not LA supplementation. LGG supplementation significantly enhanced the intestinal barrier function, increased the body weight and the survival rate in nude mice that exposed to DON for two weeks. Furthermore, LGG supplementation modulated the gut microbiota by increasing the abundance of Bacteroidetes and the levels of the butyrate-producing genes But and Buk to promote butyrate production. Butyrate inhibited the IRE1α/XBP1 signaling pathway to reduce DON-induced intestine injury. In conclusion, LGG supplementation modulated the gut microbiota to promote butyrate production, protecting against DON exposure in nude mice. Both LGG and butyrate show promise for use in protecting against DON exposure.

Time-dependent C5a and C5aR expression in dental pulp cells following stimulation with LTA and LPS.

Clinically, deep decay can lead to inflammation in the dental pulp. Apart from the use of various materials to sooth the inflamed pulp, there is currently no adequate treatment, and the gold standard, calcium hydroxide, that is used to cover the dentin/pulp, has limited effect. Sometimes the pulp will remain infected and cause pulpitis, and ultimately, the pulp will need to be removed. The first principle of oral treatment is to protect the pulp. Therefore, it is necessary to study the immune response and regeneration of pulp cells in conditions of deep decay. Of the terminal complement system proteins, complement 5a (C5a) has the most potent effect compared to complement 3a (C3a) and complement 4a (C4a). C5a is 20- to 2,500-fold stronger than C3a and C4a. The purpose of this study was to elucidate the association between C5a, secreted by complement activation, and the duration of inflammation. Another key goal was to detect the expression of C5a and its receptor, complement 5a receptor (C5aR). To this end, the cells were divided into 4 groups as per stimulation with lipoteichoic acid (LTA) or lipopolysaccharide (LPS) as follows: i) The 1 µg/ml LTA group; ii) the 1 µg/ml LPS group; iii) the 1 µg/ml LTA and 1 µg/ml LPS group; and iv) the PBS-only group, which served as a control. There were 5 time points for all 4 groups: 1, 2, 3, 5 and 7 days. Reverse transcription-quantitative polymerase chain reaction was used to detect the gene expression levels of C5a, C5aR and interleukin (IL)-6 at different time points. Western blot analyses was carried out to detect the expression of C5aR. Transmission electron microscopy was also conducted to assess the ultrastructural features of dental pulp cells. The gene expression trends of C5a and C5aR mRNA were identical. C5a and C5aR mRNA was highly expressed on the second day of LTA or LPS stimulation. However, in the LTA and LPS co-stimulation group, C5a and C5aR mRNA were highly expressed on both the first and second day, with higher levels on the second day. IL-6 expression decreased as time progressed in the LTA only and in the LTA + LPS co-stimulation groups. However, a peak in its expression was observed on the second day in the LPS group. On the whole, this study demonstrates that a 1 µg/ml concentration of LTA and LPS stimulates human dental pulp cells to activate the expression of C5a.

Loss of Fam20c causes defects in the acinar and duct structure of salivary glands in mice.

Family with sequence similarity 20­member C (FAM20C), a recently characterized Golgi kinase, performs numerous biological functions by phosphorylating more than 100 secreted proteins. However, the role of FAM20C in the salivary glands remains undefined. The present study demonstrated that FAM20C is mainly located in the cytoplasm of duct epithelial cells in the salivary glands. Fam20cf/f; Mmtv­Cre mice were created in which Fam20c was inactivated in the salivary gland cells and observed that the number of ducts and the ductal cross­sectional area increased significantly, while the number of acinar cells was reduced. The granular convoluted tubules (GCTs) exhibited an accumulation of aberrant secretory granules, along with a reduced expression and altered distribution patterns of ß nerve growth factor, α­amylase and bone morphogenetic protein (BMP) 4. This abnormality suggested that the GCT cells were immature and exhibited defects in developmental and secretory functions. In accordance with the morphological alterations and the reduced number of acinar cells, FAM20C deficiency in the salivary glands significantly decreased the salivary flow rate. The Na+, Cl- and K+ concentrations in the saliva were all significantly increased due to dysfunction of the ducts. Furthermore, Fam20c deficiency significantly increased BMP2 and BMP7 expression, decreased BMP4 expression, and attenuated the canonical and noncanonical BMP signaling pathways in the salivary glands. Collectively, the results of the present study demonstrate that FAM20C is a key regulator of acinar and duct structure and duct maturation and provide a novel avenue for investigating novel therapeutic targets for oral diseases including xerostomia.

EGR1 is essential for deoxynivalenol-induced G2/M cell cycle arrest in HepG2 cells via the ATF3ΔZip2a/2b-EGR1-p21 pathway.

Deoxynivalenol (DON) is a type B trichothecene mycotoxin that exerts multiple toxic effects on plants, animals and humans. Several reports have shown that DON leads to G2/M cell cycle arrest. However, its molecular mechanism is still unclear. In this study, we showed that DON induced strong G2/M cell cycle arrest in HepG2 cells, and the cell cycle-inhibitory protein p21 was highly upregulated by DON. Further analysis showed that the cell cycle regulating gene EGR1 was highly induced by DON and that EGR1 knockdown abolished the upregulation of p21 and G2/M cell cycle arrest. Furthermore, we showed that the induction of EGR1 was regulated by the stress-responsive transcription factor ATF3. ATF3ΔZip2a/2b, which is a DNA binding domain truncated isoform of ATF3, was upregulated by DON. ATF3 knockdown weakened the expression induction of EGR1 and G2/M cell cycle arrest by DON. Moreover, the upregulation of ATF3ΔZip2a/2 highly depended on the enhanced presence of histones H3K9ac and H3K27ac. H3K9ac and H3K27ac were enriched at the promoter region of ATF3 following the DON treatment, and the knocking down of the genes responsible for H3K9ac and H3K27ac abolished the upregulation of ATF3 by DON. In summary, we found that DON induced G2/M cell cycle arrest by sequentially inducing the expression of ATF3ΔZip2a/2b, EGR1 and p21, and EGR1 played an essential role in this process, which is a novel molecular mechanism of cell cycle arrest by DON and is important for understanding its toxicology.

Aspirin-induced attenuation of adipogenic differentiation of bone marrow mesenchymal stem cells is accompanied by the disturbed epigenetic modification.

Aspirin has positive effects on bone marrow mesenchymal stem cells (BMSCs) osteogenic differentiation. However, researchers did not give much thought to its effect on BMSCs adipogenic differentiation. Here, we analyzed the effect of aspirin on the BMSCs adipogenic differentiation. To detect whether the effect of aspirin on the adipogenic differentiation of BMSCs is associated with the disturbed epigenetic modification, the expression of histone deacetylases (HDACs), activity of HDACs and HAT, global histone H3 acetylation and H3k9 acetylation alterations were investigated. Moreover, to further explore and understand the binding mode between aspirin and HDACs, an attempt was made to identify the interaction between aspirin and the HDACs with the aid of in silico docking study. The results showed that aspirin could induce inhibition of BMSCs adipogenesis. The level of HDAC activity, global histone H3 acetylation, and H3k9 acetylation were all down regulated during adipogenic differentiation, and aspirin can reverse these decreases. Furthermore, the HDAC isoforms have different expression patterns in those progresses. The expression of HDAC9 was increased in a does-dependent manner when aspirin was introduced during BMSCs adipogenic differentiation. Docking study showed that high affinity of HDAC9 to aspirin was existed, suggesting that HDAC9 may has an important role in the process of aspirin-induced suppression of adipogenesis. Further studies are needed to define the intricate mechanisms of the HDAC isoforms, and all of these enable us to understand aspirin and its efficacy of inhibition of adipogenic differentiation and pave the way to aspirin clinical using for the tissue regenerating.

[Role of Survivin gene on the apoptosis of adenoid cystic carcinoma-2 cells induced by arsenic trioxide].

OBJECTIVE: To investigate the proliferation effects of arsenic trioxide (As2O3) on salivary adenoid cystic carcinoma-2 (ACC-2) cells in vitro and to study the role of Survivin on the apoptosis of ACC-2 induced by As2O3. METHODS: ACC-2 cells were treated with different concentration of As2O3 for different time. The inhibitory effects on cell's viability were assayed with methyl thiazolyl tetrazolium (MTT) test. Apoptosis was determined by flow cytometry. The expression of Survivin mRNA and protein were investigated by reverse transcription-polymerase chain raction (RT-PCR) and Western blot analysis respectively. RESULTS: Cell viability after As2O3 treatment was markedly suppressed and exhibited as a dose- and time-dependent pattern. The apoptotic index showed the similar trend. The results of RT-PCR revealed gene expression of Survivin was suppressed significantly. Through Western blot analysis, a negative correlation between concentration and amount of protein product of Survivin was determined. CONCLUSION: As2O3 might markedly suppressed ACC-2 cell's viability in vitro. The inhibition of Survivin gene expression may play a critical role on ACC-2 cell apoptosis induced by As2O3.