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J Immunol. 2015 Nov 15;195(10):4841-52. doi: 10.4049/jimmunol.1402654. Epub 2015 Oct 5.

Ptpn22 and Cd2 Variations Are Associated with Altered Protein Expression and Susceptibility to Type 1 Diabetes in Nonobese Diabetic Mice.

Author information

1
Juvenile Diabetes Research Foundation/Wellcome Trust Diabetes and Inflammation Laboratory, Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom;
2
Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037; La Jolla Institute for Allergy and Immunology, Type 1 Diabetes Research Center, La Jolla, CA 92037;
3
Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA 92037;
4
Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, CA 92037;
5
Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115;
6
Department of Pharmacology, Merck Research Laboratories, Rahway, NJ 07065; and.
7
The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1HH, United Kingdom.
8
Juvenile Diabetes Research Foundation/Wellcome Trust Diabetes and Inflammation Laboratory, Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, United Kingdom; linda.wicker@cimr.cam.ac.uk.

Abstract

By congenic strain mapping using autoimmune NOD.C57BL/6J congenic mice, we demonstrated previously that the type 1 diabetes (T1D) protection associated with the insulin-dependent diabetes (Idd)10 locus on chromosome 3, originally identified by linkage analysis, was in fact due to three closely linked Idd loci: Idd10, Idd18.1, and Idd18.3. In this study, we define two additional Idd loci--Idd18.2 and Idd18.4--within the boundaries of this cluster of disease-associated genes. Idd18.2 is 1.31 Mb and contains 18 genes, including Ptpn22, which encodes a phosphatase that negatively regulates T and B cell signaling. The human ortholog of Ptpn22, PTPN22, is associated with numerous autoimmune diseases, including T1D. We, therefore, assessed Ptpn22 as a candidate for Idd18.2; resequencing of the NOD Ptpn22 allele revealed 183 single nucleotide polymorphisms with the C57BL/6J (B6) allele--6 exonic and 177 intronic. Functional studies showed higher expression of full-length Ptpn22 RNA and protein, and decreased TCR signaling in congenic strains with B6-derived Idd18.2 susceptibility alleles. The 953-kb Idd18.4 locus contains eight genes, including the candidate Cd2. The CD2 pathway is associated with the human autoimmune disease, multiple sclerosis, and mice with NOD-derived susceptibility alleles at Idd18.4 have lower CD2 expression on B cells. Furthermore, we observed that susceptibility alleles at Idd18.2 can mask the protection provided by Idd10/Cd101 or Idd18.1/Vav3 and Idd18.3. In summary, we describe two new T1D loci, Idd18.2 and Idd18.4, candidate genes within each region, and demonstrate the complex nature of genetic interactions underlying the development of T1D in the NOD mouse model.

PMID:
26438525
PMCID:
PMC4635565
DOI:
10.4049/jimmunol.1402654
[Indexed for MEDLINE]
Free PMC Article

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