Chemokines Up-Regulated in Epithelial Cells Control Senescence-Associated T Cell Accumulation in Salivary Glands of Aged and Sjögren's Syndrome Model Mice.

Immunosenescence is characterized by age-associated changes in immunological functions. Although age- and autoimmune-related sialadenitis cause dry mouth (xerostomia), the roles of immunosenescence and cellular senescence in the pathogenesis of sialadenitis remain unknown. We demonstrated that acquired immune cells rather than innate immune cells infiltrated the salivary glands (SG) of aged mice. An analysis of isolated epithelial cells from SG revealed that the expression levels of the chemokine CXCL13 were elevated in aged mice. Senescence-associated T cells (SA-Ts), which secrete large amounts of atypical pro-inflammatory cytokines, are involved in the pathogenesis of metabolic disorders and autoimmune diseases. The present results showed that SA-Ts and B cells, which express the CXCL13 receptor CXCR5, accumulated in the SG of aged mice, particularly females. CD4+ T cells derived from aged mice exhibited stronger in vitro migratory activity toward CXCL13 than those from young mice. In a mouse model of Sjögren's syndrome (SS), SA-Ts also accumulated in SG, presumably via CXCL12-CXCR4 signaling. Collectively, the present results indicate that SA-Ts accumulate in SG, contribute to the pathogenesis of age- and SS-related sialadenitis by up-regulating chemokines in epithelial cells, and have potential as therapeutic targets for the treatment of xerostomia caused by these types of sialadenitis.

Human odontogenic epithelial cells derived from epithelial rests of Malassez possess stem cell properties.

Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of the Hertwig's epithelial root sheath (HERS) that are involved in the formation of tooth roots. ERM cells are unique epithelial cells that remain in periodontal tissues throughout adult life. They have a functional role in the repair/regeneration of cement or enamel. Here, we isolated odontogenic epithelial cells from ERM in the periodontal ligament, and the cells were spontaneously immortalized. Immortalized odontogenic epithelial (iOdE) cells had the ability to form spheroids and expressed stem cell-related genes. Interestingly, iOdE cells underwent osteogenic differentiation, as demonstrated by the mineralization activity in vitro in mineralization-inducing media and formation of calcification foci in iOdE cells transplanted into immunocompromised mice. These findings suggest that a cell population with features similar to stem cells exists in ERM and that this cell population has a differentiation capacity for producing calcifications in a particular microenvironment. In summary, iOdE cells will provide a convenient cell source for tissue engineering and experimental models to investigate tooth growth, differentiation, and tumorigenesis.

Mutations in the gene encoding fibroblast growth factor 10 are associated with aplasia of lacrimal and salivary glands.

Autosomal dominant aplasia of lacrimal and salivary glands (ALSG; OMIM 180920 and OMIM 103420) is a rare condition characterized by irritable eyes and dryness of the mouth. We mapped ALSG to 5p13.2-5q13.1, which coincides with the gene fibroblast growth factor 10 (FGF10). In two extended pedigrees, we identified heterozygous mutations in FGF10 in all individuals with ALSG. Fgf10(+/-) mice have a phenotype similar to ALSG, providing a model for this disorder. We suggest that haploinsufficiency for FGF10 during a crucial stage of development results in ALSG.

Novel effects of rooibos extract on tear and saliva secretion mediated by the muscarinic acetylcholine receptor 3 in mice.

OBJECTIVES: Sicca syndrome is characterized by dry mouth and eyes and results in a reduction of the patient's quality of life. Various natural plants, including certain herbs, have long been employed to alleviate such symptoms. Rooibos grown in South Africa is one of the potent herbal plants used for the treating dry mouth. However, the precise mechanism of action by which rooibos alleviates symptoms of dryness remains unclear. METHODS: The in vivo effects of rooibos extract (RE), which comprises eriodictyol-6-C-glucoside, on the secretory function of saliva and tears were analyzed after intraoral RE administration using wild-type C57BL/6 (B6) mice. In addition, the mechanisms of RE were investigated after administration of a muscarinic acetylcholine receptor 3 (M3R) antagonist. RESULTS: Tear and saliva volumes in mice increased significantly and in a dose-dependent manner following intraoral RE administration compared to those in mice in the control group administered H2O. An experiment performed using darifenacin administration revealed that the effects of RE on secretory function were exerted via M3R. CONCLUSION: These results suggest that RE administration is an effective treatment for symptoms of dryness and may be used in clinical settings against sicca syndrome.

Establishment and characterization of a clear cell odontogenic carcinoma cell line with EWSR1-ATF1 fusion gene.

OBJECTIVE: Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic tumor (MOT) characterized by sheets and lobules of vacuolated and clear cells. To understand the biology of CCOC, we established a new cell line, CCOC-T, with EWSR1-ATF1 fusion gene from a mandible tumor with distant metastasis and characterized this cell line. MATERIALS AND METHODS: To detect the EWSR1-ATF1 fusion gene, we used three CCOC cases, including the present case, by RT-PCR and FISH analysis. We characterized established CCOC-T cells by checking cell growth, invasion and the expression of odontogenic factors and bone-related factors. Moreover, the gene expression profile of CCOC-T cells was examined by microarray analysis. RESULTS: Histologically, the primary tumor was comprised of cords and nests containing clear and squamoid cells separated by fibrous septa. In addition, ameloblastomatous islands with palisaded peripheral cells were observed, indicating probable odontogenic origin. This tumor expressed the fusion gene EWSR1-ATF1, which underlies the etiology of hyalinizing clear cell carcinoma (HCCC) and potentially that of CCOC. We found a breakpoint in the EWSR1-ATF1 fusion to be the same as that reported in HCCC. Established CCOC-T cells grew extremely slowly, but the cells showed highly invasive activity. Moreover, CCOC-T cells expressed bone-related molecules, odontogenic factors, and epithelial mesenchymal transition (EMT)-related molecules. CONCLUSION: To the best of our knowledge, this is the first report on the establishment of a CCOC cell line. CCOC-T cells serve as a useful in vitro model for understanding the pathogenesis and nature of MOT.

The role of caspase cascade on the development of primary Sjögren's syndrome.

Primary Sjögren syndrome (SS) is an autoimmune disease characterized by diffuse lymphoid cell infiltrates in the salivary and lacrimal glands, resulting in symptoms of dry eye and dry mouth due to insufficient secretion. Previously, we have identified the 120 kDa alpha-fodrin as an important autoantigen on the development of SS in both animal model and SS patients, but the mechanism of a -fodrin cleavage leading to tissue destruction in SS remains unclear. In murine primary SS model, tissue-infiltrating CD4+ T cells purified from the salivary glands bear a large proportion of Fas ligand (FasL), and the salivary gland duct cells constitutively possess Fas. Infiltrating CD4+ T cells identified significant 51Cr release against mouse salivary gland (MSG) cells. In vitro studies demonstrated that apoptotic MSG cells result in a specific alpha-fodrin cleavage into 120 kDa, and preincubation with caspase-inhibitor peptides blocked alpha-fodrin cleavage. The treatment with caspase-inhibitors in vivo prevented the development of autoimmune lesions in the salivary and lacrimal glands. Thus, an increased activity in caspase cascade may be involved in the progression of alpha-fodrin proteolysis and tissue destruction on the development of SS.