Identification of candidate genes for Sjogren's syndrome using MRL/lpr mouse model of Sjogren's syndrome and cDNA microarray analysis

Sjogren's syndrome is a chronic autoimmune disease characterized by focal lymphocytic infiltration of lacrimal and salivary Glands, but the precise mechanism of this syndrome is poorly understood. To clarify the mechanism of onset and progression of Sjogren's syndrome, it is necessary to identify Sjogren's syndrome-related genes. For this purpose, we used MLR/MpJ-1pr/lpr(MRL/lpr) mouse as a model of human Secondary Sjogren's syndrome and analyzed specific mRNA expression pattern in MRL/lpr mouse salivary glands by in-house cDNA microarray. Among arrayed 2304 genes, 13 genes were isolated as highly expressed genes in MRL/lpr mouse salivary gland in comparison with MRL/MpJ-(+/+) (MRL/+) mouse tissue. Subsequently, we performed RTPCR analysis and confirmed the high expression level of nine genes; caspase3, Ly-6C.2, vimentin, Mel-14 antigen, cathepsin B, mpt1, Laptm5, Gnai2 and UCP2. Five of the nine genes have already been identified in patients with Sjogren's syndrome or mice models of the syndrome, but the remaining four genes; mpt1, Laptin5, Gnai2, and UCP2 have not been reported previously as Sjogren's syndrome-related Genes. Although, further experiments are necessary to examine the relationship between these four genes and Sjogren's syndrome, our system of mouse model of Sjogren's syndrome combined with in-house cDNA microarray is suitable for the isolation of Sjogron's syndronic-related genes. (C) 2002 Elsevier Science B.V. All rights reserved.