Botulinum toxin type a blocks aquaporin 5 trafficking by decreasing synaptosomal-associated protein 23 in submandibular acinar cells.

The trafficking of aquaporin 5 (AQP5) is critical for salivary secretion. Synaptosomal-associated protein 23 (SNAP23) is an important regulator in the process of membrane fusion. However, the role of SNAP23 on AQP5 trafficking has not been explored. Botulinum toxin type A (BoNT/A) is a bacterial toxin that effectively treats sialorrhea. We previously reported that BoNT/A induced AQP5 redistribution in cultured acinar cells, but the mechanism remained unclear. In this study, SNAP23 was predominantly localized to the plasma membrane of acinar cells in the rat submandibular gland (SMG) and colocalized with AQP5 at the apical membrane of acinar cells. In stable GFP-AQP5-transfected SMG-C6 cells, the acetylcholine receptor agonist carbachol (CCh) induced trafficking of AQP5 from intracellular vesicles to the apical membrane. Furthermore, SNAP23 knockdown by siRNA significantly inhibited CCh-induced AQP5 trafficking, whereas this inhibitory effect was reversed by SNAP23 re-expression, indicating that SNAP23 was essential in AQP5 trafficking. More importantly, BoNT/A inhibited salivary secretion from SMGs, and the underlying mechanism involved that BoNT/A blocked CCh-triggered AQP5 trafficking by decreasing SNAP23 in acinar cells. Taken together, these results identified a crucial role for SNAP23 in AQP5 trafficking and provided new insights into the mechanism of BoNT/A in treating sialorrhea and thereby a theoretical basis for clinical applications.

Alteration of myoepithelial cells during botulinum toxin type A-inhibited salivary secretion.

OBJECTIVE: Intraglandular injection of botulinum toxin type A (BoNT/A) effectively treats sialorrhea. Myoepithelial cells (MECs) are essential for salivary secretion. The role of MECs in BoNT/A-inhibited salivary secretion, and its underlying mechanisms remain unknown. MATERIALS AND METHODS: BoNT/A was injected into rat submandibular glands (SMGs). At 1, 2, 4, 8, and 12 weeks postinjection, salivary flow rate of SMGs was measured. Electron microscopy, immunohistochemistry, immunofluorescence, and Western blot analysis were used to detect morphological and functional changes in MECs and chemical denervation in SMGs. RESULTS: BoNT/A temporarily decreased salivary secretion in rat SMGs and this inhibitory effect lasted 4 weeks. During the inhibitory period, MECs atrophied and expressed reduced α-smooth muscle actin (α-SMA), vimentin, and phosphorylated myosin light chain 2 (p-MLC2), suggesting that BoNT/A attenuated MEC contractility. Furthermore, BoNT/A cleaved synaptosome-associated protein 25 (SNAP-25) and decreased the expression and activity of acetylcholinesterase (AChE), indicating that BoNT/A-induced chemical parasympathetic denervation of SMGs by cleaving SNAP-25. CONCLUSIONS: BoNT/A temporarily caused MEC atrophy and decreased MEC contractility in rat SMGs, which contributed to reversible inhibition of salivary secretion. The underlying mechanisms involved temporary parasympathetic denervation caused by SNAP-25 cleavage. These findings provide new insights into the mechanisms of BoNT/A-inhibited salivary secretion.

Photobiomodulation with 808-nm diode laser enhances gingival wound healing by promoting migration of human gingival mesenchymal stem cells via ROS/JNK/NF-κB/MMP-1 pathway.

Photobiomodulation (PBM) has been shown to improve wound healing by promoting mesenchymal stem cell migration and proliferation. However, it remains unknown whether an 808-nm diode laser can influence human gingival mesenchymal stem cells (HGMSCs), and which dose this works well. In the present study, it was found that PBM could promote the migration of HGMSCs but not the proliferation. Furthermore, PBM could activate mitochondrial ROS, which could elevate the phosphorylation levels of JNK and IKB in HGMSCs, and further activate NF-κB as the nuclear translocation of p65 is elevated. Taken together, these present results indicate that PBM might promote cell migration via the ROS/JNK/NF-κB pathway.

[Regulation effect of serum IFN-γ and IL-4 expression on immune response in patients with oral lichen planus].

PURPOSE: To investigate the regulation effect of interferon-γ (IFN-γ) and interleukin-4 (IL-4) in the serum of patients with oral lichen planus (OLP) on immune response. METHODS: A total of 83 OLP patients in Wangfujing Branch of Beijing Stomatological Hospital, Capital Medical University from January 2019 to December 2021 were selected as the experimental group, and another 61 healthy volunteers who came to the hospital during the same period were included as the control group. The expression levels of IFN-γ and IL-4 in the serum and the expression of immune function indexes of the two groups were compared. The relationship between the expression levels of IFN-γ, IL-4 and immune function indicators in the experimental group was analyzed. SPSS 22.0 software package was used to analyze the data. RESULTS: The levels of IFN-γ and IL-4 in the experimental group were significantly higher than those in the control group(P＜0.05). There was no significant difference in the levels of IFN-γ between patients with reticulated OLP and erosive OLP in the experimental group (P＞0.05). The level of IL-4 in patients with erosive OLP in the experimental group was significantly higher than that in patients with reticulated OLP(P＜0.05). The levels of CD3+, CD4, CD16++CD56+ and CD4+/CD8+ in the experimental group were significantly lower than those in the control group(P＜0.05), the levels of CD8+ and CD19+ in the experimental group were significantly higher than those in the control group(P＜0.05). The levels of IgG, IgM and CH50 in the experimental group were significantly higher than those in the control group(P＜0.05), and the levels of IgA, C3 and C4 in the experimental group were significantly lower than those in the control group(P＜0.05). Pearson correlation analysis showed that the level of IFN-γ in the experimental group was negatively correlated with CD16++CD56+ and CD4+/CD8+ (P＜0.05), the level of IL-4 in the experimental group was negatively correlated with CD16++CD56+ and CD4+/CD8+(P＜0.05), and the level of IL-4 in the experimental group was positively correlated with IgG (P＜0.05). CONCLUSIONS: Serum IFN-γ and IL-4 in OLP patients are abnormally high, and IL-4 expression is significantly higher in erosive OLP patients. The cellular and humoral immune functions of OLP patients are disordered and related to the regulation of CD16++CD56+, CD4+/CD8+, and IgG immune responses.

Analysis of the Prevalence, Location, and Morphology of Maxillary Sinus Septa in a Northern Chinese Population by Cone Beam Computed Tomography.

Purpose: The purpose of this study is to survey the prevalence and morphology of the maxillary sinus septum, which might increase the rate of maxillary sinus membrane perforation during maxillary sinus floor elevation surgery, among northern Chinese, and to further analyze the relationship between gender, age, edentulous type, and prevalence of maxillary sinus septa. Methods: The cross-sectional retrospective study was based on an analysis of Cone Beam Computed Tomography (CBCT) images of maxillary sinus which had been obtained from patients who visited radiology department of Beijing Stomatology Hospital of Capital Medical University (Beijing, China) during the period from January 2019 to December 2019. The data of demographic characteristic, prevalence, position, direction, and morphology of maxillary sinus septum were collected and further analyzed by SPSS version 25.0.1 and R version 3.5.1 software program. Results: 595 patients were included in this study, and 1190 maxillary sinuses were analyzed and the incidence rate of the sinus septum was 46.9%. 399 (33.5%) sinuses had one or more septa in 279 (46.9%) patients. In addition, maxillary sinus septa incidence showed no significant differences among gender, age, and edentulous type. The segment second molar had the highest incidence rate of septa. Conclusion: In this study, a higher incidence of the maxillary sinus septum was found in the northern Chinese, and its distribution varied with its position, morphology, and direction.

[Comparative study of submucosal microbial ecological environment between human peri-implantitis and healthy implants].

PURPOSE: To investigate the balance of submucosal microbial ecological environment in human peri-implantitis and healthy implants. METHODS: The patients with peri-implantitis and dental implants in Beijing Stomatological Hospital, and followed up for one year from September 2017 to January 2019 were enrolled. Patients were divided into two groups according to the presence or absence of peri-implantitis, i.e. peri-implantitis group (43, 51 implants) and healthy group (59 patients, 63 implants). The probing depth, bone resorption, probing bleeding, mPLI and mSBI were recorded. DNA of the submucosal microflora was extracted using a microbial gene extraction kit and sequenced by Illumina's MiSeq sequencing platform. Logistic regression analysis was used to analyze the correlation between the dominant bacteria and the average maximum probing depth, mPLI grading and MSBI grading in peri-implantitis group. The data were processed by SPSS 23.0 software package. RESULTS: The average maximum probing depth of peri-implantitis group was significantly higher than that in healthy group (P<0.05). The proportion of mPLI grade 2 in peri-implantitis group was significantly higher than that in healthy group [56.86%(29/51) vs 0.00%(0/63), P<0.05]. The proportion of mSBI grade 2 in peri-implantitis group was significantly higher than that in healthy group [60.78%(31/51) vs 0.00%(0/63), P<0.05]. The Simpson index of peri-implantitis group was significantly higher than that of the healthy group, and the Shannon index was significantly lower than the healthy group (P<0.05). In peri-implantitis group, the dominant microflora were Selenomonas (16.35%), Pseudomonas (11.20%), Fusobacterium (10.05%), Streptococcus (7.63%) and Treponema (6.84%). CONCLUSIONS: Compared with healthy implants, submucosal microorganisms of peri-implantitis have high species abundance and low species evenness, Pseudomonas, Selenomonas, Fusobacterium, Streptococcus and Treponema account for high proportions in the dominant bacteria.

[Inhibiting effects of GW2974 on DMBA-induced hamster buccal pouch carcinogenesis].

OBJECTIVE: To evaluate the inhibiting effects of GW2974, a tyrosine kinase inhibitors, on dimethyl-benzanthracene (DMBA)-induced Syrian golden hamster buccal pouch carcinogenesis. METHODS: Ninety hamsters were painted with 0.5% DMBA in the left buccal pouches three times a week for 6 weeks, which were then divided into 3 groups: low-concentration, high-concentration and positive control groups. Positive control group received no further treatment. Ten hamsters served as negative control. The two treated groups were topically painted with GW2974 (4 mmol/L) and GW2974 (8 mmol/L) three times a week, respectively. Tissue samples of the left cheek pouch were obtained at 24 th week. The average number, average volume and burden of tumor, incidence of tumor and the pathological changes of each group were recorded. RESULTS: After GW2974 (4 mmol/L and 8 mmol/L) was applied topically, tumor incidence decreased from 80.0% (24/30) to 43.3% (13/30, P < 0.01) and 36.7% (11/30, P < 0.01) respectively, the average number of tumors decreased from 1.00 +/- 0.87 to 0.47 +/- 0.82 (P < 0.05) and 0.37 +/- 0.62 (P < 0.05), the average volume and burden of tumors also declined, tumor incidence decreased from 70.0% (21/30) to 40.0% (12/30, P < 0.05) and 33.3% (10/30, P < 0.01), the number of tumors declined from 1.83 +/- 1.91 to 0.67 +/- 0.99 (P < 0.05) and 0.43 +/- 0.68 (P < 0.01). CONCLUSIONS: Topical application of GW2974 could significantly inhibit hamster buccal pouch carcinogenesis, which suggests that GW2974 may have a major impact in chemoprevention and treatment of oral cancer.