Surface-induced changes in the conformation and glucan production of glucosyltransferase adsorbed on saliva-coated hydroxyapatite.

Glucosyltransferases (Gtfs) from S. mutans play critical roles in the development of virulent oral biofilms associated with dental caries disease. Gtfs adsorbed to the tooth surface produce glucans that promote local microbial colonization and provide an insoluble exopolysaccharides (EPS) matrix that facilitates biofilm initiation.

α-Mangostin disrupts the development of Streptococcus mutans biofilms and facilitates its mechanical removal.

α-Mangostin (αMG) has been reported to be an effective antimicrobial agent against planktonic cells of Streptococcus mutans, a biofilm-forming and acid-producing cariogenic organism. However, its anti-biofilm activity remains to be determined. We examined whether αMG, a xanthone purified from Garcinia mangostana L grown in Vietnam, disrupts the development, acidogenicity, and/or the mechanical stability of S.

Symbiotic relationship between Streptococcus mutans and Candida albicans synergizes virulence of plaque biofilms in vivo.

Streptococcus mutans is often cited as the main bacterial pathogen in dental caries, particularly in early-childhood caries (ECC). S. mutans may not act alone; Candida albicans cells are frequently detected along with heavy infection by S.

Tmem16A encodes the Ca2+-activated Cl- channel in mouse submandibular salivary gland acinar cells.

Activation of an apical Ca(2+)-dependent Cl(-) channel (CaCC) is the rate-limiting step for fluid secretion in many exocrine tissues. Here, we compared the properties of native CaCC in mouse submandibular salivary gland acinar cells to the Ca(2+)-gated Cl(-) currents generated by Tmem16A and Best2, members from two distinct families of Ca(2+)-activated Cl(-) channels found in salivary glands. Heterologous expression of Tmem16A and Best2 transcripts in HEK293 cells produced Ca(2+)-activated Cl(-) currents with time and voltage dependence and inhibitor sensitivity that resembled the Ca(2+)-activated Cl(-) current found in native salivary acinar cells.

Cftr and ENaC ion channels mediate NaCl absorption in the mouse submandibular gland.

Cystic fibrosis is caused by mutations in CFTR, the cystic fibrosis transmembrane conductance regulator gene. Disruption of CFTR-mediated anion conductance results in defective fluid and electrolyte movement in the epithelial cells of organs such as the pancreas, airways and sweat glands, but the function of CFTR in salivary glands is unclear. Salivary gland acinar cells produce an isotonic, plasma-like fluid, which is subsequently modified by the ducts to produce a hypotonic, NaCl-depleted final saliva.

Systematic comparison of the human saliva and plasma proteomes.

The proteome of human salivary fluid has the potential to open new doors for disease biomarker discovery. A recent study to comprehensively identify and catalog the human ductal salivary proteome led to the compilation of 1166 proteins. The protein complexity of both saliva and plasma is large, suggesting that a comparison of these two proteomes will provide valuable insight into their physiological significance and an understanding of the unique and overlapping disease diagnostic potential that each fluid provides.

Lymphocytes from P2X7-deficient mice exhibit enhanced P2X7 responses.

The purinergic receptor P2X(7) is expressed on immune cells, and its stimulation results in the release of IL-1beta from macrophages. Its absence, as evidenced from the analysis of two independent strains of P2X(7)-deficient mice, results in reduced susceptibility to inflammatory disease, and the molecule is an important, potential therapeutic target in autoimmunity. However, P2X(7) has also been detected in several neuronal cell types, although its function and even its presence in these cells are highly contested, with anti-P2X(7) antibodies staining brain tissue from both strains of P2X(7)(-/-) mice identically to wild-type mice.

Proteomic analysis of human parotid gland exosomes by multidimensional protein identification technology (MudPIT).

Human ductal saliva contributes over a thousand unique proteins to whole oral fluids. The mechanism by which most of these proteins are secreted by salivary glands remains to be determined. The present study used a mass spectrometry-based, shotgun proteomics approach to explore the possibility that a subset of the proteins found in saliva are derived from exosomes, membrane-bound vesicles of endosomal origin within multivesicular endosomes.

Purinergic P2X7 receptors mediate ATP-induced saliva secretion by the mouse submandibular gland.

Salivary glands express multiple isoforms of P2X and P2Y nucleotide receptors, but their in vivo physiological roles are unclear. P2 receptor agonists induced salivation in an ex vivo submandibular gland preparation. The nucleotide selectivity sequence of the secretion response was BzATP >> ATP > ADP >> UTP, and removal of external Ca(2+) dramatically suppressed the initial ATP-induced fluid secretion ( approximately 85%).

Clcn2 encodes the hyperpolarization-activated chloride channel in the ducts of mouse salivary glands.

Transepithelial Cl(-) transport in salivary gland ducts is a major component of the ion reabsorption process, the final stage of saliva production. It was previously demonstrated that a Cl(-) current with the biophysical properties of ClC-2 channels dominates the Cl(-) conductance of unstimulated granular duct cells in the mouse submandibular gland. This inward-rectifying Cl(-) current is activated by hyperpolarization and elevated intracellular Cl(-) concentration.

Na+ modulates anion permeation and block of P2X7 receptors from mouse parotid glands.

We previously reported that mouse parotid acinar cells display anion conductance (I(ATPCl)) when stimulated by external ATP in Na+-free extracellular solutions. It has been suggested that the P2X7 receptor channel (P2X7R) might underlie I(ATPCl). In this work we show that I (ATPCl) can be activated by ATP, ADP, AMP-PNP, ATPgammaS and CTP.

A variant of the Ca2+-activated Cl channel Best3 is expressed in mouse exocrine glands.

Fluid secretion by exocrine glands requires the activation of an apical Ca2+-dependent Cl channel, the molecular identity of which is unknown. We found that mouse exocrine glands expressed an alternately spliced variant of Best3, a member of the Bestrophin (Vmd2) Ca2+-activated Cl channel gene family, whereas the heart expressed full-length Best3. The spliced transcript lacked exons 2, 3 and 6 (Best3-Delta2,3,6) and is predicted to generate an in-frame protein missing the entire cytoplasmic N terminus, the initial two transmembrane domains and part of the first intracellular loop.

The proteomes of human parotid and submandibular/sublingual gland salivas collected as the ductal secretions.

Saliva is a body fluid with important functions in oral and general health. A consortium of three research groups catalogued the proteins in human saliva collected as the ductal secretions: 1166 identifications--914 in parotid and 917 in submandibular/sublingual saliva--were made. The results showed that a high proportion of proteins that are found in plasma and/or tears are also present in saliva along with unique components.

Sequential shrinkage and swelling underlie P2X7-stimulated lymphocyte phosphatidylserine exposure and death.

Patterns of change in cell volume and plasma membrane phospholipid distribution during cell death are regarded as diagnostic means of distinguishing apoptosis from necrosis, the former being associated with cell shrinkage and early phosphatidylserine (PS) exposure, whereas necrosis is associated with cell swelling and consequent lysis. We demonstrate that cell volume regulation during lymphocyte death stimulated via the purinergic receptor P2X7 is distinct from both. Within seconds of stimulation, murine lymphocytes undergo rapid shrinkage concomitant with, but also required for, PS exposure.

Enhanced formation of a HCO3- transport metabolon in exocrine cells of Nhe1-/- mice.

Cl(-) influx across the basolateral membrane is a limiting step in fluid production in exocrine cells and often involves functionally linked Cl(-)/HCO(3)(-) (Ae) and Na(+)/H(+) (Nhe) exchange mechanisms. The dependence of this major Cl(-) uptake pathway on Na(+)/H(+) exchanger expression was examined in the parotid acinar cells of Nhe1(-/-) and Nhe2(-/-) mice, both of which exhibited impaired fluid secretion. No change in Cl(-)/HCO(3)(-) exchanger activity was detected in Nhe2-deficient mice.

Electrophoretic analysis of whole saliva and prevalence of dental caries. A study in Mexican dental students.

Background: Variability in salivary proteins and their posttranslational modifications may play an important role in determining their protective features against dental caries. Knowledge of molecular content of saliva in different populations is important for a better understanding of protective properties of this biological fluid. Aims of this study were to analyze electrophoretic pattern and protein composition in resting human whole saliva (HWS) of a Mexican population and to correlate these data with decayed, missing, and filled teeth (DMFT) index in these subjects.