Abstract
Abstract: :
Purpose: To semi-quantitatively analyze the expression of selected cell signaling proteins in pre-autoimmune NOD mice, a genetic model of Sjogren’s syndrome (SS). Methods: Lacrimal glands were obtained from male and female NOD (n = 4) and BALB/c controls (n = 2) at 1mo. At 1mo, there is no evidence of lymphocytic infiltration of lacrimal glands in this genetic model. Lacrimal gland lysates were solubilized and prepared for SDS-PAGE by homogenization and ultracentrifugation. A 250µg protein sample was applied to a single gel and the separated proteins were transferred to membranes for immunoblotting. The quantitative expression of 75 different protein kinases used validated commercial antibodies in the KinetworksTM KPKS 1.0 analysis (Kinexus Bioinformatics Corp, Vancouver, Canada). Data were normalized to the total counts on the blots to correct for differences in the protein amounts. Results: Of the 75 protein kinases probed, 50 were detected across all samples. Striking differences in the expression of serine/threonine protein kinases important for T lymphocyte signaling and proliferation were detected. Altered expression of 4 kinases was present in both male and female NOD mice as compared to BALB/c controls prior to the development of the autoimmune state. In NOD males, the expression of hematopoetic progenitor kinase 1 (HPK1), a Ste20-related kinase was 257% of control BALB/c expression. In female NOD’s HPK1 expression was 209% of control. Stress activated protein kinase (SAPK), downstream from HPK1, was expressed at a higher level in both male (307% of control) and female (217% of control) NOD mice. Germinal centre kinase (GCK), which belongs to the same kinase subgroup as HPK1, was elevated in male NOD’s (258% of control). The inhibitor NFΚB kinase (IKKa), also downstream from HPK1 and GCK, was reduced to 31% of BALB/c control levels in female NOD mice. Conclusions: The signaling molecules that are altered in NOD lacrimal glands are within cascades important for T cell signaling and proliferation. The data indicate upregulation of these pathways in NOD mice and suggest a mechanism for the development of lymphocytic infiltration of the gland that is characteristic of the autoimmune state. CR:none Support NIH EY07380
Keywords: animal model • lacrimal gland • autoimmune disease