Figure 6

Risedronate significantly increased the expression level of FDPS mRNA and decreased the expression level of desmoglein-2 (DSG2) mRNA in mice. (A) DNA microarray analysis of the mRNA expressions of desmoglein (DSG) in non-treated mouse taste buds (fungiform and circumvallate papillae). Microarray analysis identified 3 subtypes of DSG (DSG1, -2, -3) that were positively expressed in both taste buds. Bar graph showing the microarray signal intensity for each gene in the fungiform papillae (FP, gray bars) and circumvallate papillae (CV, black bars). (B) Real-time PCR was used to determine the mRNA expressions of taste-related genes in the CV of mice administered vehicle (Ctrl, white bars) or 15 mg/kg body weight risedronate (Rise, blue bars) three times per week for 28 days. Data were obtained from at least three independent experiments per group, and each PCR assay was performed in duplicate. The quantitative PCR results were normalized using the ΔΔCt method with glyceraldehyde-3-phosphate dehydrogenase (Gapdh) as the reference and are shown as the fold-change in mRNA expression compared to the control. All data are presented as the mean ± SEM (n = 3–11 mice). *P < 0.05 (Student's t-test, see Table 6). (C) Expression of desmoglein-1 (DSG1), DSG2 and DSG3 in the CV of mice administered vehicle (Ctrl) or risedronate (Rise) for 28 days. The risedronate-treated mice exhibited no obvious morphological changes such as intercellular space enlargement or stratum corneum thinning in comparison to control mice. Immunostaining for DSG1/2/3 is shown in yellow-green. The immunostained images are overlaid with Nomarski images. Dotted lines outline individual taste buds. Scale bars: 50 μm. Actb actin beta, CA4 carbonic anhydrase-4, DSG1/2/3 desmoglein-1/2/3, ENaC epithelial sodium channel, FDPS farnesyl diphosphate synthase, Krt8/10 keratin-8/10, Otop1 otopetrin-1, PKD polycystic kidney disease, T1R2/3 taste receptor type 1 member 2/3, Trpm5 transient receptor potential cation channel subfamily M member 5.