Monitoring gene expression of TNFR family members by beta-cells during development of autoimmune diabetes

Autoimmune diabetes results from destruction of pancreatic beta-cells by is let-infiltrating leukocytes. Different molecular mechanisms seem to be invo lved in this destruction but the results from many studies have not provide d a clear picture so far. Therefore, we have developed a multiplex single-c ell reverse transcription polymerase chain reaction to analyze the expressi on of genes of the tumor necrosis factor receptor (TNFR) family in pancreat ic beta-cells during the development of autoimmune diabetes in a TCR-HA x I NS-HA double transgenic as well as a non-obese diabetic (NOD) animal model. To this end we have followed the expression of cell surface receptors of t he TNFR family in NOD mice as well as in double transgenic mice that expres s in their T cells class II MHC-restricted TCR specific for peptide 111-119 from influenza hemagglutinin (TCR-HA) as well as hemagglutinin under the c ontrol of the rat insulin promoter (INS-HA). Both types of mice develop ins ulitis and diabetes spontaneously. The data show a significant increase in the expression of Fas and TNFR2 (p75) during the development of insulitis, whereas TNFR1 (p55) is already expressed in beta-cells before the onset of insulitis. As ligands for these receptors are already expressed at high lev els during the phase of insulitis, it is possible that beta-cell death is r egulated by intracellular inhibitors of apoptosis pathways.