Xylitol stimulates saliva secretion via muscarinic receptor signaling pathway

Xylitol is well-known to have an anti-caries effect by inhibiting the replication of cariogenic bacteria. In addition, xylitol enhances saliva secretion. However, the precise molecular mechanism of xylitol on saliva secretion is yet to be elucidated. Thus, in this study, we aimed to investigate the stimulatory effect of xylitol on saliva secretion and to further evaluate the involvement of xylitol in muscarinic type 3 receptor (M3R) signaling. For determining these effects, we measured the saliva flow rate following xylitol treatment in healthy individuals and patients with dry mouth. We further tested the effects of xylitol on M3R signaling in human salivary gland (HSG) cells using real-time quantitative reverse-transcriptase polymerase chain reaction, immunoblotting, and immunostaining. Xylitol candy significantly increased the salivary flow rate and intracellular calcium release in HSG cells via the M3R signaling pathway. In addition, the expressions of M3R and aquaporin 5 were induced by xylitol treatment. Lastly, we investigated the distribution of M3R and aquaporin 5 in HSG cells. Xylitol was found to activate M3R, thereby inducing increases in Ca²⁺ concentration. Stimulation of the muscarinic receptor induced by xylitol activated the internalization of M3R and subsequent trafficking of aquaporin 5. Taken together, these findings suggest a molecular mechanism for secretory effects of xylitol on salivary epithelial cells.

Effect of α-Fodrin siRNA on human salivary gland cells / 重庆医学

Objective To observe the effect of α‐Fodrin siRNA on human salivary gland(HSG)cells and to discuss its thera‐py on sj?gren′s syndrome(SS) .Methods The vectors expressing siRNA againstα‐Fodrin of human were transfected into HSG cells of 10μg α‐fodrin siRNA1 group andα‐Fodrin siRNA2 group ,while pGFP‐V‐RS vector were transfected into the cells of empty vec‐tor group ,there was no handling in HSG cell of control group .The efficiency was observed by fluorescence microscope after trans‐fection of 24 ,48 ,72 and 96 h by lipofectamine 2000 .The expression levels of α‐Fodrin mRNA and protein of HSG were detected by real‐time(RT)‐PCR and immunohistochemistry method respectively .The expression levels of IFN‐γ and IL‐10 in supernatant of cells were detected by ELISA .Results The efficiency was highest on 48 h after transfection .The level of α‐Fodrin mRNA and pro‐tein was lower in α‐fodrin siRNA1 group and α‐fodrin siRNA2 group than control group and empty vector group on 48 h after transfection (P0 .05) .The levels IFN‐γ in α‐fodrin siRNA1 group and α‐fodrin siRNA2 group were lower than of control group and empty vector group on 48 h after transfection ,but there were no significant differences in the four groups (P>0 .05) .Conclusion Theα‐fodrin siRNA1 andα‐fodrin siRNA2 can suppress the levels of α‐fodrin mRNA and protein of HSG cells ,at the same time;they can elevate the expression of IL‐10 and decrease the level of IFN‐γ.Soα‐Fodrin siRNA reduce the levels of inflammatory cyto‐kines and provide experimental basis to therapy of SS .