C-X-C motif chemokine ligand 1 and its receptor C-X-C motif chemokine receptor 2 in trigeminal ganglion contribute to nerve injury-induced orofacial mechanical allodynia.

BACKGROUND: Orofacial ectopic pain induced by trigeminal nerve injury is a serious complication of dental treatment. C-X-C motif chemokine ligand 1 (CXCL1) and its primary receptor C-X-C motif chemokine receptor 2 (CXCR2) contribute to the development and maintenance of neuropathic pain in the spinal nervous system, but their roles in trigeminal neuropathic sensation are still poorly understood. OBJECTIVES: This study aimed to investigate the exact role of CXCL1 and CXCR2 in the regulation of orofacial ectopic mechanical allodynia and their potential downstream mechanisms in the trigeminal ganglion (TG). METHODS: The head withdrawal threshold (HWT) of C57BL/6 mice was evaluated after inferior alveolar nerve (IAN) transection (IANX). Then, the distribution and expression of CXCL1 and CXCR2, and their potential downstream mechanisms in the TG were further measured using immunohistochemistry, real-time reverse transcription-quantitative polymerase chain reaction and Western blotting. Moreover, the effect of SB225002 (an inhibitor of CXCR2) on mechanical allodynia was examined. The data were analysed using the Student's t test and a analysis of variance (ANOVA). RESULTS: IANX triggered persistent (>21 days) mechanical allodynia and upregulation of CXCL1 and CXCR2 in the TG. In addition, exogenous CXCL1 also lowered the HWT, which was alleviated by CXCR2 and protein kinase C (PKC) antagonists (p < .05). In addition, IANX increased the phosphorylated PKC (p-PKC) levels and decreased the expression of voltage-gated potassium channels (Kv), and these effects were reversed by inhibition of CXCR2 (p < .05). CONCLUSION: Our results demonstrated that CXCR2 participated in orofacial ectopic mechanical allodynia via downregulation of Kv1.4 and Kv1.1 through the PKC signalling pathway. This mechanism may be a potential target in developing a treatment strategy for ectopic orofacial pain.

Effect of Titanium Particles on the Voltage-Gated Potassium Channel Currents in Trigeminal Root Ganglion Neurons.

PURPOSE: Titanium (Ti) is the key material used in dental implants because of its excellent biocompatibility. But wear and corrosion Ti particles had been widely reported to induce inflammation and promote bone absorption. However, little information is known about the damage of Ti particles on neurons. MATERIALS AND METHODS: Trigeminal root ganglion (TRG) neurons were exposed to Ti particles (<5 µm). The electrophysiological properties of 2 main subtypes of voltage-gated potassium channels (VGPCs) (KA and KV) were examined by whole-cell patch-clamp techniques. RESULT: With the presence of 0.25 mg/mL Ti particles, amplitudes of IK, A and IK, V were both obviously inhibited. For IK, A, the activation V1/2 shifted to the depolarizing direction with an increased k value, whereas the inactivation V1/2 showed obvious hyperdepolarizing shifts. For IK, V, 0.5 mg/mL Ti particles produced a depolarizing shift of activation V1/2 with a slower activation rate. No significant changes of its inactivation kinetics were found. CONCLUSION: Titanium (Ti) particles might alter the electrophysiological properties of VGPCs on TRG neurons, which are likely to further influence the excitability of neurons.

Single cell RNA sequencing reveals mesenchymal heterogeneity and critical functions of Cd271 in tooth development.

BACKGROUND: Accumulating evidence suggests that the maxillary process, to which cranial crest cells migrate, is essential to tooth development. Emerging studies indicate that Cd271 plays an essential role in odontogenesis. However, the underlying mechanisms have yet to be elucidated. AIM: To establish the functionally heterogeneous population in the maxillary process, elucidate the effects of Cd271 deficiency on gene expression differences. METHODS: p75NTR knockout (Cd271-/-) mice (from American Jackson laboratory) were used to collect the maxillofacial process tissue of p75NTR knockout mice, and the wild-type maxillofacial process of the same pregnant mouse wild was used as control. After single cell suspension, the cDNA was prepared by loading the single cell suspension into the 10x Genomics Chromium system to be sequenced by NovaSeq6000 sequencing system. Finally, the sequencing data in Fastq format were obtained. The FastQC software is used to evaluate the quality of data and CellRanger analyzed the data. The gene expression matrix is read by R software, and Seurat is used to control and standardize the data, reduce the dimension and cluster. We search for marker genes for subgroup annotation by consulting literature and database; explore the effect of p75NTR knockout on mesenchymal stem cells (MSCs) gene expression and cell proportion by cell subgrouping, differential gene analysis, enrichment analysis and protein-protein interaction network analysis; understand the interaction between MSCs cells and the differentiation trajectory and gene change characteristics of p75NTR knockout MSCs by cell communication analysis and pseudo-time analysis. Last we verified the findings single cell sequencing in vitro. RESULTS: We identified 21 cell clusters, and we re-clustered these into three subclusters. Importantly, we revealed the cell-cell communication networks between clusters. We clarified that Cd271 was significantly associated with the regulation of mineralization. CONCLUSION: This study provides comprehensive mechanistic insights into the maxillary- process-derived MSCs and demonstrates that Cd271 is significantly associated with the odontogenesis in mesenchymal populations.

[Effects of Microplastic Exposure on Crucian Growth, Liver Damage, and Gut Microbiome Composition].

Microplastics (MPs), which are widely present in the natural environment, may be harmful to the growth and health of aquatic organisms, though studies in this area are lacking. In this study, the crucian carp (Carassius carassius), a type of omnivorous freshwater fish, was chosen as the target, which was fed with fish food containing different concentrations of MPs for a 30-day food exposure experiment to study the effects of MPs on crucian growth, liver damage, and gut microbiome composition. Compared with that in the control group, the body length of the crucians in the environmental groups did not change significantly. The weight of the crucians in the low PE-MPs group increased significantly, but the weight of crucians in the medium and high PE-MPs groups decreased markedly. The liver tissues of the low PE-MPs group of crucians were basically normal, whereas crucians in the medium and high PE-MPs groups had varying degrees of liver damage, and crucians in the high PE-MPs group had the most serious liver damage. At the phylum level, Proteobacteria, Fusobacteria, Firmicutes, and Bacteroides were the dominant species in the gut of the crucians. Pathogens such as Staphylococcus and Ralstonia were present in the crucian gut of environmental groups. Alpha diversity results showed that the gut microbiome of crucians in the high PE-MPs group was the most abundant. PCoA results indicated that the gut microbiome of crucians in the control and environmental groups had obvious clustering characteristics.

Natural developing process of immunoglobulin G4-related sialadenitis after submandibular gland excision: a retrospective cohort study.

OBJECTIVE: This study aimed to evaluate the long-term outcome and quality of life of IgG4-related sialadenitis (IgG4-RS) patients after submandibular gland (SMG) excision without immunomediate therapy. MATERIALS AND METHODS: This retrospective review included patients with IgG4-RS who did not undergo further treatment following SMG excision. All patients diagnosed with IgG4-RS between January 1955 and December 2012 at the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology, were enrolled. The main outcome measures included postoperative IgG4-RS progression rate and differences between patients with and without recurrent disease. The degree of subjective oral dryness was evaluated using the summated xerostomia inventory (SXI); the objective secretory function was assessed by whole saliva flow rate measurements. Serological findings were analyzed during the follow-up. RESULTS: SMG excision was adopted in all of the 83 patients. The median follow-up period was 108 (range 7-396) months. Clinical progression was observed in 54.2% of cases. Patients with other organ involvement (OOI) indicated higher progression rate to a significant extent (P = 0.015, HR = 2.108). The annual progression rate was 20.7% in the group with OOI and was 14.1% in the group without OOI. All cases showed higher levels of serum IgG4; the level was in positive correlation with follow-up time when no therapy was added. 82.4% of cases experienced xerostomia after the surgery, and the degree of dry mouth in patients underwent bilateral resection was significantly more severe than those in unilateral resection. CONCLUSIONS: Surgical excision of involved SMG cannot control the disease progression, which is not recommended for treatment of IgG4-RS. Differential diagnosis is crucial in order to prevent irreversible organ loss and relevant salivary gland dysfunction. Key Points • Surgical excision of involved SMG cannot control progression of IgG4-RS.

Clinical features for 89 deaths of hand, foot and mouth disease in Guangxi, China, 2014.

OBJECTIVES: The aim of this study is to summarize the risk factors of severe Hand, foot and mouth disease (HFMD) and explore the clinical characteristics of pulmonary edema (PE) and non-PE in the deceased patients with HFMD. METHODS: We identified 89 HFMD deaths which were separated into the PE group or non-PE group. Next, patients were divided based on their initial admission to hospitals as stage 1, 2, 3, or 4; at this point, their clinical manifestations were compared. RESULTS: There were 87 cases in the PE group, and 2 cases in the non-PE group. In the PE group, the difference in median time for patients at different stages from onset to symptoms, showed no significant difference (p>0.05). The etiology was detected as a positive rate for enterovirus 71 (EV71) of 89.19%, which showed a more severe course than other etiologies. The white blood cell (WBC) counts, lymphocyte (LYM) counts and creatine kinase MB (CK-MB) counts of patients admitted in different stages increased significantly with severity (p<0.05). CONCLUSIONS: There may be two clinical subtypes, mostly PE and rarely non-PE, in the deceased patients with HMFD. EV71 and risk factors such as an increased WBC count are associated with a severe course of HMFD.

[Inhibition of A549 cells by polybutylcyanoacrylate nanoparticles loaded with antisense oligodeoxynucleotide of hTERT mRNA].

AIM: To investigate the effect of nanoparticles for antisense oligodeoxynucleotide (ASODN) of hTERT mRNA on A549 cells. METHODS: The cationic polybutylcyanoacrylate nanoparticles (NPs) were prepared by an emulsion polymerization process in the presence of DEAE-dextran. Antisense oligodeoxynucleotides were loaded on the particles by adsorption. The cytotoxicity of NPs and proliferation of A549 cells were detected by MTT assay. Intracellular fluorescence intensity after transfecting the 5'-FITC-labelled ASODN (FASODN) and cell cycles were determined by flow cytometry (FCM). Inverse microscope was used to observe the modality of A549 cell transfected by NPs for ASODN. The protein expression of hTERT was measured by immunocytochemistry. RESULTS: The cytotoxicity increased evidently with the increasing concentration of NPs over 2.5 g x L(-1). The intracellular fluorescence in FASODN-NP group was obviously stronger than that in FASODN group (NPs free) after transfection for 24 h (P < 0.01). The inhibitory rate for cell modality change and proliferation after the treatment with ASODN-NP at 72 h reached peak , 62.4% , 44.6% and 36.4% for ASODN1-NP group, ASODN2-NP group and ASODN3-NP group, respectively; The cell cycle in ASODN-NP group varied observably compared with control group and sense oligodeoxynucleotide-nanoparticle (SODN-NP) group and the cell cycle was blocked in G1 phase, the cell number in S phase decreased obviously (P < 0.01); The hTERT protein expression of ASODN-NP group reduced clearly. CONCLUSION: ASODN-NP of hTERT can inhibit the proliferation of A549 cells effectively and cause the change of cell cycle, restraint of protein expression of hTERT and cell viability.