BioProject

In both NOD mice and humans, the development of type 1 diabetes (T1D) is dependent in part on autoreactive CD8+ T-cells recognizing pancreatic ß-cell peptides presented by often quite common MHC class I variants. More...

In both NOD mice and humans, the development of type 1 diabetes (T1D) is dependent in part on autoreactive CD8+ T-cells recognizing pancreatic ß-cell peptides presented by often quite common MHC class I variants. Studies in NOD mice previously revealed the common H2-Kd and/or H2-Db class I molecules expressed by this strain acquire an aberrant ability to mediate pathogenic CD8 T-cell responses through interactions with T1D susceptibility (Idd) genes outside the MHC. A gene(s) mapping to the Idd7 locus on proximal Chromosome 7 was previously shown to be an important contributor to the failure of the common class I molecules expressed by NOD mice to mediate the normal thymic negative selection of diabetogenic CD8+ T-cells. Using an inducible model of thymic negative selection and mRNA transcript analyses we initially identified an elevated Nfkbid expression variant as a strong candidate for an NOD Idd7 region gene contributing to impaired thymic deletion of diabetogenic CD8+ T-cells. CRISPR/Cas9-mediated genetic attenuation of Nfkbid expression in NOD mice resulted in improved negative selection of autoreactive diabetogenic AI4 and NY8.3 CD8+ T-cells. These results indicated allelic variants of Nfkbid represent an Idd7 gene contributing to the efficiency of intrathymic deletion of diabetogenic CD8+ T-cells. However, while enhancing thymic deletion of pathogenic CD8+ T-cells, ablation of Nfkbid expression surprisingly accelerated T1D onset in NOD mice likely by numerically decreasing regulatory T- and B-lymphocytes (Tregs/Bregs), thereby reducing their peripheral immunosuppressive effects. We used microarray analysis to identify differentialy expressed genes in thymus under conditions of induced thymic negative selection. We compare two mice strains, NOD-LCMV vs NOD.Ln82-LCMV (a congenic stock for a C57BL/6 derived segment delimited by markers D7Mit117–D7Mit247). Overall design: Three to five 5-week-old, NOD.LCMV and NOD.Ln82-LCMV female mice were i.v. injected with 0.5μg of gp33 (KAVYNFATM) or Db binding control peptide (ASNENMETM). Two hours post-injection, whole thymus tissue was processed for total RNA extraction. RNA samples were hybridized to Affymetrix Mouse Gene 1.0 ST Arrays. A total of 15 samples were analyzed. 3-5 biological replicates by experimental group. Less...