Mechanisms of an autoimmunity syndrome in mice caused by a dominant mutation in Aire
Maureen A. Su, … , B. Matija Peterlin, Mark S. Anderson
Maureen A. Su, … , B. Matija Peterlin, Mark S. Anderson
Published April 15, 2008
Citation Information: J Clin Invest. 2008;118(5):1712-1726. https://doi.org/10.1172/JCI34523.
View: Text | PDF
Research Article Autoimmunity

Mechanisms of an autoimmunity syndrome in mice caused by a dominant mutation in Aire

Abstract

Homozygous loss-of-function mutations in AIRE cause autoimmune polyglandular syndrome type 1 (APS 1), which manifests in a classic triad of hypoparathyroidism, adrenal insufficiency, and candidiasis. Interestingly, a kindred with a specific G228W AIRE variant presented with an autosomal dominant autoimmune phenotype distinct from APS 1. We utilized a novel G228W-knockin mouse model to show that this variant acted in a dominant-negative manner to cause a unique autoimmunity syndrome. In addition, the expression of a large number of Aire-regulated thymic antigens was partially inhibited in these animals, demonstrating the importance of quantitative changes in thymic antigen expression in determining organ-specific autoimmunity. Furthermore, the dominant-negative effect of the G228W variant was exerted through recruitment of WT Aire away from active sites of transcription in the nucleus of medullary thymic epithelial cells in vivo. Together, these results may demonstrate a mechanism by which autoimmune predisposition to phenotypes distinct from APS 1 can be mediated in a dominant-negative fashion by Aire.

Authors

Maureen A. Su, Karen Giang, Kristina Žumer, Huimin Jiang, Irena Oven, John L. Rinn, Jason J. DeVoss, Kellsey P.A. Johannes, Wen Lu, James Gardner, Angela Chang, Paula Bubulya, Howard Y. Chang, B. Matija Peterlin, Mark S. Anderson

×

Figure 1

The G228W-knockin mouse expresses Aire protein.

Options: View larger image (or click on image) Download as PowerPoint
The G228W-knockin mouse expresses Aire protein. (A) Schematic of the fir...
(A) Schematic of the first 8 exons of targeted G228W allele. The asterisk marks the site of the missense mutation. Arrowheads flanking the neo cassette represent loxP sites. The targeting construct is indicated by the dotted line, and the 5′ and 3′ ends are marked with vertical dotted lines. A single loxP remained after Cre-mediated neo excision in ES cells (bottom). (B) Southern blot of electroporated ES cell clones using a probe external to the construct (shown in A) to ascertain homologous recombination. Banding pattern of genomic DNA cut with KpnI from WT (left) and a targeted ES cell clone (right) are shown. Lanes were run on the same gel but were noncontiguous. (C) DNA (first line) and amino acid (second line) sequences around G228W point mutation. The mutated codon is outlined with a rectangle. (D) Immunohistochemical staining of thymi for cytokeratin 5 (red) and Aire (green). Scale bar: 100 μm. (E) Top: Quantitation of number of Aire-positive cells per area of thymic medulla in thymic sections. Bottom: Quantitation of the thymic medullary areas per section of Aire+/+ (n = 17) and AireGW/+ (n = 13) thymi. Sections were randomly selected from at least 3 different mice per genotype. Averages ± SD are shown. (F) Histogram of Aire expression by flow cytometry in mTEChi (red) cells, cortical thymic epithelial cells (cTECs) (green) cells, and isotype control (blue). Numbers represent average ± SD within gated region of mTEChi cells; MFI is presented as mean ± SD (n = 3 for each genotype).