Age and Gender Related Changes in Human Parotid Gland Gene Expression

Previous studies suggest that there may be age and gender related differences in salivary gland function. However, the limited and often conflicting information available from healthy populations makes it difficult to confirm these differences. The purpose of the present study was to evaluate and compare changes in gene expression associated with age and gender in the human parotid gland. Differential expression, defined as statistically significant differences with at least 1.5 fold changes, was detected using the Affymetrix GeneChip HGU133plus2.0 microarray in 787 gene probe sets; 320 showed higher expression in males, while 467 showed higher expression in females. Several genes associated with saliva secretion were differentially expressed in male and female parotid gland including vesicle-associated membrane protein 3 VAMP3, synaptosomal-associated protein SNAP23, RAS oncogene family member RAB1A, syntaxin binding protein STXBP1. When the gene expression results from the youngest (19-38 years old) and the oldest (65-69 years old) female subjects were further evaluated, it was found that the expression of 228 genes were altered during aging; 155 genes were down-regulated, whereas 73 genes were up-regulated in the female parotid gland. Of the genes that were altered during aging, 24 of the 28 genes (86%) classified as being associated with immune responses were down-regulated in the aged parotid gland. A panel of differentially expressed, age- and gender-related genes was selected for further study by quantitative, real-time RT-PCR. Comparable differences in gene expression were detected by both Affymetrix array and quantitative, real-time RT-PCR methods. Taken together, our data suggest that salivary gland function may be adversely affected in the aged population due, at least in part, to the down regulation of several categories of genes. Moreover, the gender specific gene expressions identified in the present study correlates with the previously observed sexual dimorphism in salivary gland function.

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Srivastava A, Wang J, Zhou H, Melvin JE, Wong DT