Expression of aquaporin 3 and 5 as a potential marker for distinguishing dry mouth from Sjögren's syndrome.

A study was performed to investigate whether expression of aquaporin (AQP) 3 and 5 has potential as a marker for distinguishing dry mouth from Sjögren's syndrome. Twenty-five patients underwent labial minor salivary gland biopsy (dry mouth, n = 9; Sjögren's syndrome, n = 16; control, n = 8). All patients were interviewed about their medical history and subjective oral symptoms, and intraoral examinations were conducted. Quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry were used to examine the expression and localization of AQP3 and 5. Significant differences in oral dryness, dry eye, medical history, and Saxon test results were revealed among the groups. However, there were no significant inter-group differences in expression of mRNA for AQP3 and 5. Immunohistochemical staining for AQP3 was localized mainly in the basolateral and part of the ductal cell membrane, and was barely evident in the apical membrane of acinar cells. AQP5 was localized to the basolateral and apical membrane and cytoplasm, but not the ductal cell membrane. Staining intensity for AQP3 in the apical membrane was significantly stronger in Sjögren's syndrome, and that for AQP5 was significantly weaker in dry mouth. Taken together, the present data suggest that expression of AQP3 and 5 may be a marker for distinguishing between patients with dry mouth and those with Sjögren's syndrome.

Oral microbiome alterations of healthy volunteers with proton pump inhibitor.

BACKGROUND AND AIM: Acid suppressive agents including proton pump inhibitors (PPIs) are used as first-line treatment for various acid-related gastrointestinal disorders. Although known to profoundly reduce gastric acid production, their influence on inhibition of acid secretion as part of the function of the gastrointestinal tract microbiome remains to be elucidated. The aim of the present study was to examine the effects of PPI usage on oral and gut microbiota in healthy volunteers. METHODS: Ten healthy adult volunteers receiving no medications were enrolled. We obtained fecal, saliva, and periodontal pocket fluid samples from the subjects before and after 4 weeks of once daily administrations of 20-mg esomeprazole. The effects of PPI administration on bacterial communities were investigated using a 16S rRNA gene sequencing method. RESULTS: Species richness (alpha diversity) was significantly different among the salivary, periodontal pocket, and fecal samples. Furthermore, the measurements for UniFrac distances, despite inter-individual variations (beta diversity), of the microbiota structure of saliva and periodontal pocket and feces samples were clearly separated from each other. The salivary samples showed significant differences between alpha and beta diversity measurements before and after administration of the PPI for 4 weeks. Meanwhile, taxon-based analysis indicated that PPI administration raised the ratio of Streptococcus organisms in fecal samples, suggesting a potentially unfavorable effect leading to gut microbiota alteration. Moreover, alterations of the microbiota in the oral carriage microbiome along with bacterial overgrowth (Streptococcus) and decreases in distinct bacterial species (Neisseria and Veillonella) were observed. CONCLUSIONS: These results suggest that PPIs cause both oral and gut microbiota alterations.

G196 epitope tag system: a novel monoclonal antibody, G196, recognizes the small, soluble peptide DLVPR with high affinity.

The recognition specificity of monoclonal antibodies (mAbs) has made mAbs among the most frequently used tools in both basic science research and in clinical diagnosis and therapies. Precise determination of the epitope allows the development of epitope tag systems to be used with recombinant proteins for various purposes. Here we describe a new family of tag derived from the epitope recognized by a highly specific mAb G196. The minimal epitope was identified as the five amino acid sequence Asp-Leu-Val-Pro-Arg. Permutation analysis was used to characterize the binding requirements of mAb G196, and the variable regions of the mAb G196 were identified and structurally analyzed by X-ray crystallography. Isothermal titration calorimetry revealed the high affinity (Kd = 1.25 nM) of the mAb G196/G196-epitope peptide interaction, and G196-tag was used to detect several recombinant cytosolic and nuclear proteins in human and yeast cells. mAb G196 is valuable for developing a new peptide tagging system for cell biology and biochemistry research.