Expression of Toll-like Receptors and Beta-defensins During Development of Sialoadenitis

Objectives: Toll-like receptors (TLR) play a fundamental role in the activation of the innate immune system during infection. Beta-defensins (BDs) belong to a group of antimicrobial peptides expressed mainly in epithelial cells, which contribute to both innate and adaptive immunity. Although expression of TLRs and BDs has been detected in the salivary gland, there is little information on the expression profiles in the salioadenitis. Non-obese diabetic (NOD) mice spontaneously develop sialoadenitis, producing a condition that resembles Sjogren's syndrome. The present study analyzed the expression patterns of BD-1,-2 and -3, and TLR-2,-3,-4,-7,-8 and -9 during the development of sialoadenitis in NOD mice. Method: Female NOD mice (ClEA, Japan) were used in the present study. Submandibular glands were dissected from the mice at 4,8,10,12,14 and 16 weeks of age (n=5 in each group). Expression of BD-1,-2 and -3, and TLR-2,-3,-4,-7,-8 and -9 and myeloid differentiation factor 88 (MyD88) was observed by RT-PCR and quantitative RT-PCR using TaqMan probes (Applied Biosystem, CA). Several experiments were performed, each in triplicate. The relative expression of each mRNA was calculated as the ΔCt using the formula described by Saitoh et al.(Med Mol Morphol, 2007). The data was analyzed using one-way ANOVA. Differences between experimental groups were considered statistically significant at the p<0.05 levels. Results: The submandibular glands show no indication of inflammatory reactions in 4- and 8-week-old mice. Ten-week-old mice generally had one focus of lymphatic infiltration per lobule. Expression levels of BD-2 and -3 at 14 and 16 weeks were significantly higher than at 4 or 8 weeks (p<0.01). Expression levels of TRL-2,-3,-4 and -7 and MyD88 were significantly higher than at 4 or 8 weeks (p<0.01). Conclusion: The results indicate that BD-2 and -3, and TRL-2,-3,-4 and -7 and MyD88 may be upregulated during the development of autoimmune sialoadenitis.