Differential expression of Toll‐like receptors in chronic hyperplastic candidosis

Introduction: The first step in the host defense against oral candidosis is the recognition of Candida albicans through a set of germ‐encoded pathogen recognition receptors, e.g. Toll‐like receptors (TLRs). In man, 10 types of such receptors have been identified so far, of which only TLR2, TLR4, and TLR6 have been linked to mediating candidal ligands, e.g. zymosan. Methods: Biopsies from patients with chronic hyperplastic candidosis (n = 5), leukoplakia (n = 5), and healthy mucosa (n = 5) were immunohistochemically stained with antibodies to the TLRs (TLR1 to TLR9) to distinguish and compare the staining patterns of the epithelial layer in the three categories of tissues. Results: On analysis, the epithelium of all tissues was divided into three layers: basal, middle, and superficial. Two of the five chronic hyperplastic candidosis sections showed high numbers of hyphae compared to yeasts, which paralleled a decrease in the expression of TLR2 and an increase in the staining intensity of TLR4. Leukoplakia and healthy tissue sections demonstrated stronger immunostaining of TLRs, except TLR9 which showed weaker staining in some sections of the former, and in the basal layers of some sections of the latter. Discussion: This study supports the concept of negative regulation of TLRs that are either ligand‐bound (e.g. in chronic hyperplastic candidosis), or not stimulated (in healthy tissue). It also augments the opinion that C. albicans, through its hyphae rather than blastospore, may utilize TLRs, i.e. TLR2, to evade the immune system of the host. Leukoplakia seems to be more immunologically alert, which reduces the chances of worsening the already‐diseased tissue.     

Innate immune mechanisms to oral pathogens in oral mucosa of HIV‐infected individuals

A crucial aspect of mucosal HIV transmission is the interaction between HIV, the local environmental milieu and immune cells. The oral mucosa comprises many host cell types including epithelial cells, CD4 + T cells, dendritic cells and monocytes/macrophages, as well as a diverse microbiome predominantly comprising bacterial species. While the oral epithelium is one of the first sites exposed to HIV through oral‐genital contact and nursing infants, it is largely thought to be resistant to HIV transmission via mechanisms that are still unclear. HIV‐1 infection is also associated with predisposition to secondary infections, such as tuberculosis, and other diseases including cancer. This review addresses the following questions that were discussed at the 8th World Workshop on Oral Health and Disease in AIDS held in Bali, Indonesia, 13 September —15 September 2019: (a) How does HIV infection affect epithelial cell signalling? (b) How does HIV infection affect the production of cytokines and other innate antimicrobial factors, (c) How is the mucosal distribution and function of immune cells altered in HIV infection? (d) How do T cells affect HIV (oral) pathogenesis and cancer? (e) How does HIV infection lead to susceptibility to TB infections?     

Annexin‐A1 identified as the oral epithelial cell anti‐Candida effector moiety

Innate and adaptive immunity are considered critical to protection against mucosal candidal infections. Among innate anti‐Candida mechanisms, oral and vaginal epithelial cells have antifungal activity. The mechanism is fungistatic, acid‐labile and includes a requirement for cell contact by intact, but not necessarily live, epithelial cells. The purpose of this study was to use the acid‐labile property to further characterize the effector moiety. Surface material extracted from phosphate‐buffered saline (PBS) ‐treated, but not acid‐treated, epithelial cells significantly inhibited the growth of Candida blastoconidia in a dose‐dependent manner which was abrogated by prior heat and protease treatment. Proteins extracted from PBS‐treated cells bound blastoconidia and hyphae more intensely than those from acid‐treated cells. Proteins from PBS‐treated cells eluted from Candida revealed two unique bands of approximately 33 and 45 kDa compared with acid‐treated cells. Mass spectrometry identified these proteins as Annexin‐A1 and actin, respectively. Oral epithelial cells stained positive for Annexin‐A1, but not actin. Western blots showed reduced Annexin‐A1 in proteins from acid‐treated epithelial cells compared with those from PBS‐treated epithelial cells. Lastly, it was demonstrated that immunoprecipitation of Annexin‐A1 from proteins extracted from PBS‐treated oral epithelial cells resulted in abrogation of inhibitory activity. Taken together, these results indicate that Annexin‐A1 is a strong candidate for the epithelial cell anti‐Candida effector protein.     

Helicobacter pylori in the oral cavity and gastric mucosa: a meta‐analysis

J Oral Pathol Med (2011) 40 : 317–324 Background: Helicobacter pylori have been found in the oral cavity and stomach. This study is to establish whether there might be any associations between isolates of H. pylori in the oral cavity and those in the stomach by meta‐analysis. Methods: Studies reporting raw data on the prevalence of H. pylori infection in the oral cavity in gastric H. pylori‐positive and H. pylori‐negative patients, in patients with gastroesophageal diseases, and in healthy individuals and studies reporting data on the eradication rate in the oral cavity or stomach, published in the English language, were identified through MEDLINE and EMBASE up to May 2010. Results: The prevalence of H. pylori infection in the oral cavity in gastric H. pylori‐positive patients was significantly higher (45.0%) than that in gastric H. pylori‐negative patients (23.9%). The pooled odds ration (OR) was 3.61 and the 95% CI was 1.91–6.82 (P < 0.0001). Different diagnostic methods produced different pooled ORs with PCR the highest (OR = 5.11, 95% CI: 2.08–12.54, P = 0.0004) and rapid urease test (RUT) the lowest (OR = 2.00, 95% CI: 0.80–5.00, P = 0.14). The 44.8% (91/203) prevalence of H. pylori infection in the oral cavity in patients with clinical and/or histological gastroesophageal diseases was significantly higher than the 13.2% (21/159) in patients with non‐ulcerous dyspepsia or healthy controls (OR = 5.15, 95% CI: 2.97–8.92, P < 0.00001). The eradication efficiency in stomach is 85.8% (187/218), while in oral cavity it is only 5.7% (9/158). The OR is 55.59, P < 0.00001. Conclusions: There is a close relation between the infection of H. pylori in the oral cavity and stomach. H. pylori in the oral cavity are more difficult to be eradicated than in the stomach. It may be a source of reinfection.     

The role of Toll‐like receptors in periodontitis

Periodontitis is a common infectious disease. Recent studies have indicated that the progression of periodontitis may be regulated by interactions between host immunity and periodontopathic bacteria. Although periodontopathic bacteria can destroy periodontal tissue, a dysfunctional host immune response triggered by the bacteria can lead to more severe and persistent destruction. Toll‐like receptors (TLRs), a type of pattern recognition receptor (PRR) that recognizes pathogens, have been implicated in host innate immune responses to periodontopathic bacteria and in the activation of adaptive immunity. TLR‐targeted drugs may hold promise to treat periodontal disease. This review summarizes recent studies on the role of TLRs in periodontitis and discusses areas needing further research. We believe TLRs may be an effective biomarker for the prevention, diagnosis, and treatment of periodontitis in the near future.     

E‐selectin expression induced by Porphyromonas gingivalis in human endothelial cells via nucleotide‐binding oligomerization domain‐like receptors and Toll‐like receptors

Porphyromonas gingivalis, an important periodontal pathogen, has been proved to actively invade cells, induce endothelial cell activation, and promote development of atherosclerosis. Innate immune surveillance, which includes the activity of nucleotide‐binding oligomerization domain (NOD)‐like receptors (NLRs) and Toll‐like receptors (TLRs), are essential for the control of microbial infections; however, the roles of receptor families in P. gingivalis infections remain unclear. Here, we examined the roles of NLRs and TLRs in endothelial cell activation caused by P. gingivalis. Live P. gingivalis and whole cell sonicates were used to stimulate endothelial cells, and both showed upregulation of E‐selectin as well as NOD1, NOD2, and TLR2. In addition, silencing of these genes in endothelial cells infected with P. gingivalis led to a reduction in E‐selectin expression. Porphyromonas gingivalis also induced nuclear factor‐κB (NF‐κB) and P38 mitogen‐activated protein kinase (MAPK) activity in endothelial cells, whereas small interfering RNA targeting NOD1 significantly reduced these signals. Moreover, inhibition of either NOD2 or TLR2 inhibited NF‐κB significantly, but had only a weak inhibitory effect on P38 MAPK signaling. Direct inhibition of NF‐κB and P38 MAPK significantly attenuated E‐selectin expression induced by P. gingivalis in endothelial cells. Taken together, these findings suggest that NOD1, NOD2, and TLR2 play important, non‐redundant roles in endothelial cell activation following P. gingivalis infection.     

Type I interferon and interferon‐stimulated gene expression in oral epithelial cells

Oral epithelial cells (OEC) represent the first site of host interaction with viruses that infect the body through the oral route; however, their innate antiviral defense mechanisms yet to be defined. Previous studies have determined that OEC express pathogen‐, damage‐, or danger‐associated molecular patterns (PAMPs or DAMPs), but their expression of key antiviral innate immune mediators, including type I interferons (type I IFN) and interferon‐stimulated genes (ISGs) has not been studied extensively. We used the oral keratinocyte cell line, OKF6/TERT1, in the presence and absence of the viral mimics poly(I:C) and unmethylated CpG DNA, to define the expression of type I IFN and ISGs. We identified the basal expression of novel type I IFN genes IFNE and IFNK, while IFNB1 was induced by viral mimics, through the nuclear translocation of IRF3. Numerous ISGs were expressed at basal levels in OEC, with an apparent correlation between high expression and antiviral activity at the earlier stages of viral infection. Stimulation of OECs with poly(I:C) led to selective induction of ISGs, including MX1, BST2, PML, RSAD2, ISG15, and ZC3HAV1. Together, our results demonstrate that OECs exhibit a robust innate antiviral immune defense profile, which is primed to address a wide variety of pathogenic viruses that are transmitted orally.     

The oral mucosa: A barrier site participating in tissue‐specific and systemic immunity

In the oral cavity, the immune system is constantly exposed to unique tissue‐specific signals, including a rich community of commensal microbes and their metabolites, continuous tissue damage from mastication, and antigens from food and airborne particles. How this unique combination of signals participates in the training of specialized immunity at this site is not well understood, yet imbalance of local responses is linked to tissue‐specific disease susceptibilities with the prototypic disease being periodontitis. However, the oral mucosa is also well recognized as a site where systemic inflammatory and autoimmune diseases often manifest, indicating that systemic immune deregulation is reflected in the function of the oral immune system. This commentary will discuss both aspects of compartmentalized and systemic immunity at the oral mucosa.     

Gene expression analysis of neuropeptides in oral mucosa during periodontal disease in non‐human primates

1 Background

Neuropeptides (NPs) are innate pivotal regulators of the immunoinflammatory response. Nevertheless, their role in the pathogenesis of periodontal disease remains unknown. Changes in gene expression of 10 NPs and 16 NP receptors (NPRs) coincident with the initiation, progression, and resolution of periodontitis were determined.

2 Methods

The ligature‐induced periodontitis model was used in rhesus monkeys (n = 18). Gingival tissue samples were taken at baseline (preligatures), at 2 weeks and at 1 month (initiation), and at 3 months (progression) postligation. Ligatures were removed and samples taken 2 months later (resolution). Total RNA was isolated from tissues and NP/NPR gene expression microarray analysis was performed. Gene expression changes were validated by quantitative polymerase chain reaction and immunohistochemistry.

3 Results

Unexpectedly, the expression of pro‐inflammatory NPs/NPRs did not change during periodontitis or with resolution. However, increased expression of the anti‐inflammatory NPs adrenomedullin (ADM) and galanin (GAL), and the NPRs calcitonin receptor‐like (CALCRL) and receptor activity‐modifying protein‐2 and ‐3 (RAMP2 and RAMP3) were observed during initiation and progression of disease. The expression of the same NPs/NPRs exhibited a significant positive correlation with both molecular (interleukin‐1ß, matrix mettaloproteinase‐9, and receptor activator of nuclear factor‐kappa B ligand) and clinical measures of gingival inflammation and tissue destruction.

4 Conclusion

Initiation and progression of periodontitis involve significant overexpression of ADM, GAL, CALCRL, RAMP2, and RAMP3. These anti‐inflammatory NPs/NPRs could play a role in the unresolved infection and inflammation that normally drives tissue destruction in periodontitis. Both ADM and GAL potentially are new candidates to consider as biomolecules associated with periodontal disease activity.     

Quantitative messenger RNA expression of Toll‐like receptors and interferon‐α1 in gingivitis and periodontitis

Introduction: In addition to bacteria, viruses have been reportedly implicated in periodontitis. However, the available data are confined to Toll‐like receptor 2 (TLR2) and TLR4, which recognize bacterial products in periodontitis. In the present study, we investigated the expression levels of TLR5, ‐7, and ‐9 messenger RNAs (mRNAs) in addition to those of TLR2 and ‐4, and compared gingivitis and periodontitis. Interferon‐α1 (IFN‐α1), which is important for the antiviral response, was also compared. Methods: Gene expression was analyzed using quantitative real‐time polymerase chain reaction for 59 periodontitis and 27 gingivitis tissue samples together with viral serology in some patients. The presence of plasmacytoid dendritic cells (pDCs), a robust producer of IFN‐α, was immunohistochemically analyzed in an additional seven periodontitis and two gingivitis specimens. Results: The expression levels of TLR2, ‐4, ‐7, and ‐9 were significantly higher in periodontitis lesions than gingivitis lesions. The expression level of TLR5 was comparable to levels of TLR2 and ‐4; however, no significant difference was found between gingivitis and periodontitis. Although the expression of IFN‐α1 mRNA was higher in periodontitis lesions compared with gingivitis lesions, the level was quite low. Only a few pDCs were found in some periodontitis specimens. No difference was found for antibody‐positivity between gingivitis and periodontitis. Conclusion: This is the first study to show that a variety of TLRs are up‐regulated in periodontitis lesions compared with gingivitis lesions, suggesting that diverse microbial and possibly viral antigens are involved in the pathogenic mechanisms for periodontal diseases. However, the ligands recognized by the various TLRs in periodontal lesions remain to be determined.     

雌激素受体在口腔粘膜癌前病变中的表达及意义

目的阐明雌激素受体（ER）在口腔粘膜癌变过程中的表达状况及其对临床诊断、治疗的意义。方法采用链霉素抗生物素蛋白一过氧化物物酶（SP）免疫组化法，检测了口腔鳞状细胞癌（SCC）、口腔白斑（1．K）、口腔扁平苔藓（I．P）、正常口腔粘膜（NM）中的ER表达状况。结果NM中42．86％ER阳性，成灶状分布于棘细胞层内，胞浆染色均匀。IP、IK、SCC中ER阳性率分别为71．43％、60．0％、68．42％，成片位于棘层胞浆中，胞浆染色不均匀。ER表达与患者性别、病理类型无关。结论提示SCC、LK、LP中ER存在是确实的，口腔粘膜肿瘤可能是激素依赖肿瘤。但ER不宜作为监测癌变潜能的指标。