Aim Dental biofilms are complex communities composed largely of harmless bacteria. Certain pathogenic species including Streptococcus mutans （S. mutans） can become predominant when host factors such as dietary sucro...Aim Dental biofilms are complex communities composed largely of harmless bacteria. Certain pathogenic species including Streptococcus mutans （S. mutans） can become predominant when host factors such as dietary sucrose intake imbalance the biofilm ecology. Current approaches to control S. mutans infection are not pathogen-specific and eliminate the entire oral community along with any protective benefits provided. Here, we tested the hypothesis that removal of S. mutans from the oral community through targeted antimicrobial therapy achieves protection against subsequent S. mutans colonization. Methodology Controlled amounts of S. mutans were mixed with S. mutans-free saliva, grown into biofilms and visualized by antibody staining and cfu quantization. Two specifically-targeted antimicrobial peptides （STAMPs） against S. mutans were tested for their ability to reduce S. mutans biofilm incorporation upon treatment of the inocula. The resulting biofilms were also evaluated for their ability to resist subsequent exogenous S. mutans colonization. Results S. mutans colonization was considerably reduced （9 ± 0.4 fold reduction, P=0.01） when the surface was preoccupied with saliva-derived biofilms. Furthermore, treatment with S. mutans-specific STAMPs yielded S. mutans-deficient biofilms with significant protection against further S. mutans colonization （5 minutes treatment： 38 ± 13 fold reduction P=0.01; 16 hours treatment： 96 ± 28 fold reduction P=0.07）. Conclusion S. mutans infection is reduced by the pre- sence of existing biofilms. Thus maintaining a healthy or ＂normal＂ biofilm through targeted antimicrobial therapy （such as the STAMPs） could represent an effective strategy for the treatment and prevention of S. mutans colonization in the oral cavity and caries progression.展开更多
Bacterial infection is a common finding in patients,who develop medication-related osteonecrosis of the jaw(MRONJ)by the longterm and/or high-dose use of anti-resorptive agents such as bisphosphonate(BPs).However,path...Bacterial infection is a common finding in patients,who develop medication-related osteonecrosis of the jaw(MRONJ)by the longterm and/or high-dose use of anti-resorptive agents such as bisphosphonate(BPs).However,pathological role of bacteria in MRONJ development at the early stage remains controversial.Here,we demonstrated that commensal microbiota protects against MRONJ development in the pulp-exposed periapical periodontitis mouse model.C57/BL6 female mice were treated with intragastric broadspectrum antibiotics for 1 week.Zoledronic acid(ZOL)through intravenous injection and antibiotics in drinking water were administered for throughout the experiment.Pulp was exposed on the left maxillary first molar,then the mice were left for 5 weeks after which bilateral maxillary first molar was extracted and mice were left for additional 3 weeks to heal.All mice were harvested,and cecum,maxilla,and femurs were collected.ONJ development was assessed usingμCT and histologic analyses.When antibiotic was treated in mice,these mice had no weight changes,but developed significantly enlarged ceca compared to the control group(CTL mice).Periapical bone resorption prior to the tooth extraction was similarly prevented when treated with antibiotics,which was confirmed by decreased osteoclasts and inflammation.ZOL treatment with pulp exposure significantly increased bone necrosis as determined by empty lacunae and necrotic bone amount.Furthermore,antibiotics treatment could further exacerbate bone necrosis,with increased osteoclast number.Our findings suggest that the commensal microbiome may play protective role,rather than pathological role,in the early stages of MRONJ development.展开更多
Growing evidence suggests close associations between periodontitis and atherosclerosis.To further understand the pathological relationships of these associations,we developed periodontitis with ligature placement arou...Growing evidence suggests close associations between periodontitis and atherosclerosis.To further understand the pathological relationships of these associations,we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g.LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals.The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis,systemic inflammation,and atherosclerosis.Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas,but mice receiving ligature or ligature/P.g.LPS showed severe periodontitis,systemic inflammation,and aortic plaque formation.The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers.The severity of periodontitis was slightly higher in mice receiving ligature/P.g.LPS than ligature alone,and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g.LPS.These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis.In vitro,P.g.LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells.Moreover,secretory proteins,such as TNF-α,from macrophages induced endothelial–mesenchymal transitions of the endothelial cells.Taken together,systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via,in part,causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice.展开更多
Aim To determine how SDF-1α/CXCR4 activates nuclear factor-kappa B （NF-κB） and promotes oral squamous cell carcinoma （OSCC） invasion.Methodology A lentivirus-based knockdown approach was utilized to deplete gene...Aim To determine how SDF-1α/CXCR4 activates nuclear factor-kappa B （NF-κB） and promotes oral squamous cell carcinoma （OSCC） invasion.Methodology A lentivirus-based knockdown approach was utilized to deplete gene expression. NF-κB activation was evaluated by Western blot analysis and electrophoretic mobility shift （EMSA）. Results We show that the activation of NF-κB by CXCR4 occurs through the Carma3/Bcl10/Maltl （CBM） complex in OSCC. We found that loss of components of the CBM complex in HNSCC can inhibit SDF-1α induced phosphorylation and degradation of IκBα, while TNFα induced IKK activation remains unchanged. Further, we identified a role for novel and atypical, but not classical, PKCs in activating IKK through CXCR4. Importantly, inhibition of the CBM complex leads to a significant decrease in SDF-1α mediated invasion of OSCC. Conclusion The CBM complex plays a critical role in CXCR4-induced NF-κB activation in OSCC. Targeting molecular components of the NF-κB signaling pathway may provide an important therapeutic opportunity in controlling the progression and metastasis of OSCC mediated by SDF-1α.展开更多
High-risk human papillomaviruses(HPVs) are involved in the development of several human cancers, including oropharyngeal squamous cell carcinomas. However, many studies have demonstrated that HPV alone is not sufficie...High-risk human papillomaviruses(HPVs) are involved in the development of several human cancers, including oropharyngeal squamous cell carcinomas. However, many studies have demonstrated that HPV alone is not sufficient for the oncogenic transformation of normal human epithelial cells, indicating that additional cofactors are required for the oncogenic conversion of HPV-infected cells. Inasmuch as chronic inflammation is also closely associated with carcinogenesis, we investigated the effect of chronic exposure to tumor necrosis factor α(TNFα), the major proinflammatory cytokine, on oncogenesis in two immortalized oral keratinocyte cell lines, namely, HPV16-immortalized and human telomerase reverse transcriptase(h TERT)-immortalized cells. TNFαtreatment led to the acquisition of malignant growth properties in HPV16-immortalized cells, such as(1) calcium resistance,(2)anchorage independence, and(3) increased cell proliferation in vivo. Moreover, TNFα increased the cancer stem cell-like population and stemness phenotype in HPV16-immortalized cells. However, such transforming effects were not observed in h TERTimmortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated h TERT-immortalized cells that express HPV16 E6 and E7. Chronic TNFα exposure successfully induced the malignant growth and stemness phenotype in the E6-expressing cells but not in the control and E7-expressing cells. We further demonstrated that HPV16 E6 played a key role in TNFα-induced cancer stemness via suppression of the stemness-inhibiting micro RNAs mi R-203 and mi R-200 c. Overexpression of mi R-203 and mi R-200 c suppressed cancer stemness in TNFα-treated HPV16-immortalized cells. Overall, our study suggests that chronic inflammation promotes cancer stemness in HPV-infected cells, thereby promoting HPV-associated oral carcinogenesis.展开更多
Malocclusion is a worldwide dental problem that influences the affected individuals to varying degrees. Many factors contribute to the anomaly in dentition, including hereditary and environmental aspects. Dental carie...Malocclusion is a worldwide dental problem that influences the affected individuals to varying degrees. Many factors contribute to the anomaly in dentition, including hereditary and environmental aspects. Dental caries, pulpal and periapical lesions, dental trauma, abnormality of development, and oral habits are most common dental diseases in children that strongly relate to malocclusion. Management of oral health in the early childhood stage is carried out in clinic work of pediatric dentistry to minimize the unwanted effect of these diseases on dentition. This article highlights these diseases and their impacts on malocclusion in sequence. Prevention, treatment, and management of these conditions are also illustrated in order to achieve successful oral health for children and adolescents, even for their adult stage.展开更多
Background β--catenin, a 92 kDa protein that binds to the cytoplasmic tail of E-cadherin, has an essential role in intercellular adhesion and signal transduction. Aberrant expression of β-catenin has been associated...Background β--catenin, a 92 kDa protein that binds to the cytoplasmic tail of E-cadherin, has an essential role in intercellular adhesion and signal transduction. Aberrant expression of β-catenin has been associated with progression and metastasis of various human cancers. The aim of this study was to elucidate the expression pattern of β-catenin in primary oral squamous cell carcinoma and examine the correlation between β-catenin expression and tumor differentiation, histological grade and lymph node status as well as its clinical significances. Methods Seventy-six patients with oral squamous cell carcinoma and sixteen metastatic lymph nodes were studied. The β-catenin expression was determined by immunohistochemical staining. The correlation with clinical, histological data was analyzed statistically. Results Normal oral epithelium showed strong β-catenin expression at the cell membrane, but no cytoplasmic or nuclear expression. Different degrees of reduced expression of β-catenin at the cell membrane were found in 54 cases with squamous cell carcinoma （71%）. Cytoplasmic β-catenin expression was found in 17 tumors （22.4%）. Three cases were found with nuclear β-catenin expression. In sixteen lymph nodes with metastatic squamous cell carcinoma, negative β-catenin expression at the cell membrane was seen in 13 tumors （81.2%） and weak expression in 3 tumors （18.8%）. Statistical analysis showed that there was an inverse correlation between β-catenin expression and lymph node status and histological grade of tumors. Conclusions Reduced β-catenin expression at the cell membrane is clearly associated with lymph node metastasis. A reduced expression of β-catenin may constitute a hallmark of aggressive biological behavior of squamous cell carcinoma.展开更多
文摘Aim Dental biofilms are complex communities composed largely of harmless bacteria. Certain pathogenic species including Streptococcus mutans （S. mutans） can become predominant when host factors such as dietary sucrose intake imbalance the biofilm ecology. Current approaches to control S. mutans infection are not pathogen-specific and eliminate the entire oral community along with any protective benefits provided. Here, we tested the hypothesis that removal of S. mutans from the oral community through targeted antimicrobial therapy achieves protection against subsequent S. mutans colonization. Methodology Controlled amounts of S. mutans were mixed with S. mutans-free saliva, grown into biofilms and visualized by antibody staining and cfu quantization. Two specifically-targeted antimicrobial peptides （STAMPs） against S. mutans were tested for their ability to reduce S. mutans biofilm incorporation upon treatment of the inocula. The resulting biofilms were also evaluated for their ability to resist subsequent exogenous S. mutans colonization. Results S. mutans colonization was considerably reduced （9 ± 0.4 fold reduction, P=0.01） when the surface was preoccupied with saliva-derived biofilms. Furthermore, treatment with S. mutans-specific STAMPs yielded S. mutans-deficient biofilms with significant protection against further S. mutans colonization （5 minutes treatment： 38 ± 13 fold reduction P=0.01; 16 hours treatment： 96 ± 28 fold reduction P=0.07）. Conclusion S. mutans infection is reduced by the pre- sence of existing biofilms. Thus maintaining a healthy or ＂normal＂ biofilm through targeted antimicrobial therapy （such as the STAMPs） could represent an effective strategy for the treatment and prevention of S. mutans colonization in the oral cavity and caries progression.
基金supported National Institutes of Health/National Institute of Dental and Craniofacial Research(grant DE023348 to R.H.K.,grant DE025172 to D.W.W.)China Postdoctoral Science Foundation(grant 2019M663526 to W.D.)。
文摘Bacterial infection is a common finding in patients,who develop medication-related osteonecrosis of the jaw(MRONJ)by the longterm and/or high-dose use of anti-resorptive agents such as bisphosphonate(BPs).However,pathological role of bacteria in MRONJ development at the early stage remains controversial.Here,we demonstrated that commensal microbiota protects against MRONJ development in the pulp-exposed periapical periodontitis mouse model.C57/BL6 female mice were treated with intragastric broadspectrum antibiotics for 1 week.Zoledronic acid(ZOL)through intravenous injection and antibiotics in drinking water were administered for throughout the experiment.Pulp was exposed on the left maxillary first molar,then the mice were left for 5 weeks after which bilateral maxillary first molar was extracted and mice were left for additional 3 weeks to heal.All mice were harvested,and cecum,maxilla,and femurs were collected.ONJ development was assessed usingμCT and histologic analyses.When antibiotic was treated in mice,these mice had no weight changes,but developed significantly enlarged ceca compared to the control group(CTL mice).Periapical bone resorption prior to the tooth extraction was similarly prevented when treated with antibiotics,which was confirmed by decreased osteoclasts and inflammation.ZOL treatment with pulp exposure significantly increased bone necrosis as determined by empty lacunae and necrotic bone amount.Furthermore,antibiotics treatment could further exacerbate bone necrosis,with increased osteoclast number.Our findings suggest that the commensal microbiome may play protective role,rather than pathological role,in the early stages of MRONJ development.
基金supported, in part, by the research funds awarded from the UCLA Chancellor’s Office (N.-H.P.)NIH/NIDCR DE 023348 (R.H.K. and N.-H.P.)NIH/NHLBI HL30568 (K.I.B.)
文摘Growing evidence suggests close associations between periodontitis and atherosclerosis.To further understand the pathological relationships of these associations,we developed periodontitis with ligature placement around maxillary molars or ligature placement in conjunction with Porphyromonas gingivalis lipopolysaccharide injection at the ligature sites (ligature/P.g.LPS) in Apolipoprotein E knock out mice and studied the atherogenesis process in these animals.The mice were fed with high fat diet for 11 weeks and sacrificed for analyzing periodontitis,systemic inflammation,and atherosclerosis.Controls did not develop periodontitis or systemic inflammation and had minimal lipid deposition in the aortas,but mice receiving ligature or ligature/P.g.LPS showed severe periodontitis,systemic inflammation,and aortic plaque formation.The aortic plaque contained abundant macrophages and cells expressing both endothelial and mesenchymal cell markers.The severity of periodontitis was slightly higher in mice receiving ligature/P.g.LPS than ligature alone,and the magnitude of systemic inflammation and aortic plaque formation were also notably greater in the mice with ligature/P.g.LPS.These observations indicate that the development of atherosclerosis is due to systemic inflammation caused by severe periodontitis.In vitro,P.g.LPS enhanced the secretion of pro-inflammatory cytokines from macrophages and increased the adhesion of monocytes to endothelial cells by upregulating the expression of adhesion molecules from endothelial cells.Moreover,secretory proteins,such as TNF-α,from macrophages induced endothelial–mesenchymal transitions of the endothelial cells.Taken together,systemic inflammation induced by severe periodontitis might exacerbate atherosclerosis via,in part,causing aberrant functions of vascular endothelial cells and the activation of macrophages in mice.
基金supported by the grants DE13848 and DE15964 from National Institute of Dental and Craniofacial Research, National Institute of Health, USA
文摘Aim To determine how SDF-1α/CXCR4 activates nuclear factor-kappa B （NF-κB） and promotes oral squamous cell carcinoma （OSCC） invasion.Methodology A lentivirus-based knockdown approach was utilized to deplete gene expression. NF-κB activation was evaluated by Western blot analysis and electrophoretic mobility shift （EMSA）. Results We show that the activation of NF-κB by CXCR4 occurs through the Carma3/Bcl10/Maltl （CBM） complex in OSCC. We found that loss of components of the CBM complex in HNSCC can inhibit SDF-1α induced phosphorylation and degradation of IκBα, while TNFα induced IKK activation remains unchanged. Further, we identified a role for novel and atypical, but not classical, PKCs in activating IKK through CXCR4. Importantly, inhibition of the CBM complex leads to a significant decrease in SDF-1α mediated invasion of OSCC. Conclusion The CBM complex plays a critical role in CXCR4-induced NF-κB activation in OSCC. Targeting molecular components of the NF-κB signaling pathway may provide an important therapeutic opportunity in controlling the progression and metastasis of OSCC mediated by SDF-1α.
基金This work was supported in part by the UCLA School of Dentistry faculty seed grant(to K.-H.S.)two grants(R01DE18295 to M.K.K.and R01DE023348 to R.H.K.)from NIDCR/NIHa grant from UCLA Chancellor’s Office(to N.H.P.).
文摘High-risk human papillomaviruses(HPVs) are involved in the development of several human cancers, including oropharyngeal squamous cell carcinomas. However, many studies have demonstrated that HPV alone is not sufficient for the oncogenic transformation of normal human epithelial cells, indicating that additional cofactors are required for the oncogenic conversion of HPV-infected cells. Inasmuch as chronic inflammation is also closely associated with carcinogenesis, we investigated the effect of chronic exposure to tumor necrosis factor α(TNFα), the major proinflammatory cytokine, on oncogenesis in two immortalized oral keratinocyte cell lines, namely, HPV16-immortalized and human telomerase reverse transcriptase(h TERT)-immortalized cells. TNFαtreatment led to the acquisition of malignant growth properties in HPV16-immortalized cells, such as(1) calcium resistance,(2)anchorage independence, and(3) increased cell proliferation in vivo. Moreover, TNFα increased the cancer stem cell-like population and stemness phenotype in HPV16-immortalized cells. However, such transforming effects were not observed in h TERTimmortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated h TERT-immortalized cells that express HPV16 E6 and E7. Chronic TNFα exposure successfully induced the malignant growth and stemness phenotype in the E6-expressing cells but not in the control and E7-expressing cells. We further demonstrated that HPV16 E6 played a key role in TNFα-induced cancer stemness via suppression of the stemness-inhibiting micro RNAs mi R-203 and mi R-200 c. Overexpression of mi R-203 and mi R-200 c suppressed cancer stemness in TNFα-treated HPV16-immortalized cells. Overall, our study suggests that chronic inflammation promotes cancer stemness in HPV-infected cells, thereby promoting HPV-associated oral carcinogenesis.
基金supported by grants from the National Natural Science Foundation of China(81470035)
文摘Malocclusion is a worldwide dental problem that influences the affected individuals to varying degrees. Many factors contribute to the anomaly in dentition, including hereditary and environmental aspects. Dental caries, pulpal and periapical lesions, dental trauma, abnormality of development, and oral habits are most common dental diseases in children that strongly relate to malocclusion. Management of oral health in the early childhood stage is carried out in clinic work of pediatric dentistry to minimize the unwanted effect of these diseases on dentition. This article highlights these diseases and their impacts on malocclusion in sequence. Prevention, treatment, and management of these conditions are also illustrated in order to achieve successful oral health for children and adolescents, even for their adult stage.
文摘Background β--catenin, a 92 kDa protein that binds to the cytoplasmic tail of E-cadherin, has an essential role in intercellular adhesion and signal transduction. Aberrant expression of β-catenin has been associated with progression and metastasis of various human cancers. The aim of this study was to elucidate the expression pattern of β-catenin in primary oral squamous cell carcinoma and examine the correlation between β-catenin expression and tumor differentiation, histological grade and lymph node status as well as its clinical significances. Methods Seventy-six patients with oral squamous cell carcinoma and sixteen metastatic lymph nodes were studied. The β-catenin expression was determined by immunohistochemical staining. The correlation with clinical, histological data was analyzed statistically. Results Normal oral epithelium showed strong β-catenin expression at the cell membrane, but no cytoplasmic or nuclear expression. Different degrees of reduced expression of β-catenin at the cell membrane were found in 54 cases with squamous cell carcinoma （71%）. Cytoplasmic β-catenin expression was found in 17 tumors （22.4%）. Three cases were found with nuclear β-catenin expression. In sixteen lymph nodes with metastatic squamous cell carcinoma, negative β-catenin expression at the cell membrane was seen in 13 tumors （81.2%） and weak expression in 3 tumors （18.8%）. Statistical analysis showed that there was an inverse correlation between β-catenin expression and lymph node status and histological grade of tumors. Conclusions Reduced β-catenin expression at the cell membrane is clearly associated with lymph node metastasis. A reduced expression of β-catenin may constitute a hallmark of aggressive biological behavior of squamous cell carcinoma.
