Although an association between periodontitis and chronic kidney disease (CKD) has been suggested, the mechanism involved remains unclear. Herein, we examined the global gene expression profile in a mouse model that showed no acute inflammation in the kidney following stimulation with lipopolysaccharides (LPS) derived from Porphyromonas gingivalis (PG-LPS). The mice were injected with PG-LPS at a concentration of 5 mg/kg intraperitoneally, every 3 days, for 1 month. Microarray analysis was used to identify 10 genes with the highest expression levels in the kidney stimulated with PG-LPS. Among them, the functions of five genes (Saa3, Ticam2, Reg3b, Ocxt2a, and Xcr1) were known. The upregulation of these genes was confirmed by quantitative polymerase chain reaction assay. Furthermore, we examined whether the expression of these upregulated genes were altered in endothelial cells derived from the kidney, in vitro. The mRNA expression levels of all five genes were significantly higher in the experimental group than in the controls (no LPS stimulation; *p < 0.05). In conclusion, the responses noted in the kidney may have arisen mainly from the endothelial cells. Moreover, upregulation of the expression levels of Saa3, Ticam2, Reg3b, Ocxt2a, and Xcr1 may be associated with the pathogenesis of CKD.

Secretory carcinoma (SC) of the salivary gland was recently added to the fourth edition of the World Health Organization classification of head and neck tumors. Some salivary tumors, including acinic cell carcinoma, have been reclassified as SC. Most of these tumors are located on the parotid gland with very few cases reported in the minor salivary glands of the buccal mucosa. Herein, we present a case of SC of buccal mucosa, which appeared clinically as a benign lesion in a 54-year-old Japanese female patient. Histopathologically, the tumor cells presented with an eosinophilic cytoplasm with microcytic structure along with eosinophilic secretory material and hemosiderin deposit. Immunohistochemical staining revealed strongly positive staining for S100, vimentin, and mammaglobin and negative staining for DOG-1. The tumor was finally diagnosed as secretory carcinoma of the buccal mucosa. We present a review of the medical literature of SC arising from minor salivary glands. We found only 15 cases of SC of buccal mucosa out of 63 cases of SC in the minor salivary glands. They showed good prognoses and only one case of SC in the buccal mucosa exhibited local recurrence and lymph node metastases.

The DNA demethylating agent, 5-Azacytidine (5Aza), and histone deacetylase inhibitor, valproic acid (Vpa), can improve the reprogramming efficiencies of pluripotent cells. This study aimed to examine the roles of 5Aza and Vpa in the dedifferentiation of epithelial cell rests of Malassez (ERM) into stem-like cells. Additionally, the ability of stem-like cells to differentiate into mesenchymal cells was evaluated. ERM was cultured in embryonic stem cell medium (ESCM) with 1 µM of 5Aza, or 2 mM of Vpa, or a combination of 5Aza and Vpa. The cells stimulated with both 5Aza and Vpa were named as progenitor-dedifferentiated into stem-like cells (Pro-DSLCs). The Pro-DSLCs cultured in ESCM alone for another week were named as DSLCs. The stem cell markers were significantly higher in the DSLCs than the controls (no additions). The mRNA and protein levels of the endothelial, mesenchymal stem, and osteogenic cell markers were significantly higher in the Pro-DSLCs and DSLCs than the controls. The combination of a demethylating agent and a deacetylated inhibitor induced the dedifferentiation of ERM into DSLCs. The Pro-DSLCs derived from ERM can be directly reprogrammed into mesenchymal-like cells without dedifferentiation into stem-like cells. Isolated ERM treated with epigenetic agents may be used for periodontal regeneration.

RNase 7 is a skin-derived antimicrobial peptide expressed in various epithelial tissues. It is upregulated by stimulation with microbes and pro-inflammatory cytokines. Herein, we examined the expression levels of RNase 7 in tissues from normal and inflamed oral epithelia and salivary glands via immunohistochemistry. RNase 7 was expressed mainly in the surface layers of the parakeratinized and orthokeratinized oral epithelium. In addition, it was strongly and weakly expressed in oral lichen planus and radicular cysts, respectively. RNase 7 was constitutively expressed in salivary glands, particularly in the serous and duct cells. In the case of Sjogren’s syndrome, RNase 7 was strongly expressed in serous, ductal, and mucous cells in areas with lymphocytic infiltration. The localization patterns of RNase 7 were similar to those of other epithelial antimicrobial peptides, including beta-defensins. Thus, epithelial antimicrobial peptides may act against microbial infections in a coordinated manner in oral epithelia and salivary glands.

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