Loss of the Protein Tyrosine Phosphatase PTPN22 Reduces Mannan-Induced Autoimmune Arthritis in SKG Mice.
The cytoplasmic phosphatase, protein tyrosine phosphatase nonreceptor type 22 (PTPN22), is a negative regulator of T cell signaling. Genome-wide association studies have shown that single-nucleotide polymorphisms in PTPN22 confer an increased risk of developing multiple autoimmune diseases in humans. The precise function of PTPN22 and how the variant protein contributes to autoimmunity is not well understood. To address this issue, we investigated the effect of PTPN22 deficiency on disease susceptibility in a mouse model of autoimmune arthritis. The SKG mouse expresses a hypomorphic mutant allele of ZAP70, which, upon exposure to fungal Ags, predisposes the mice to a CD4(+) T cell-mediated autoimmune arthritis that closely resembles rheumatoid arthritis in humans. Surprisingly, SKG Ptpn22(-/-) mice developed less severe mannan-induced arthritis compared with SKG mice. Diminution of disease was not due to significant alterations in thymocyte development or repertoire selection in SKG Ptpn22(-/-) mice, even though T cell-mediated signal transduction was improved. Instead, Ptpn22 deficiency appeared to bias CD4 Th cell differentiation away from the Th17 lineage, which is pathogenic in this setting, to a more Th1/T regulatory-focused response. These data show that even small perturbations in TCR signal transduction pathways can have profound consequences on the differentiation of T cell lineages and thus for the development of autoimmune diseases.
Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; and.
Shatakshi
S
Sood
Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; and.
Rebecca J
0000-0003-4897-1044
RJ
Brownlie
Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; and.
Celine
C
Garcia
Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; and.
Graeme
0000-0002-1949-4253
G
Cowan
Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; and.
Robert J
RJ
Salmond
Experimental Immunology, Immunology Frontier Research Center, Osaka University, Suita 565-0871, Japan.
Shimon
S
Sakaguchi
Institute of Immunology and Infection Research, Ashworth Laboratories, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom; and rose.zamoyska@ed.ac.uk.
Rose
0000-0001-9816-2638
R
Zamoyska
D000818:Animals; D001169:Arthritis, Experimental / Q000276:immunology*; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D005434:Flow Cytometry; D008351:Mannans / Q000633:toxicity; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D016133:Polymerase Chain Reaction; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22 / Q000172:deficiency / Q000276:immunology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D058504:Th17 Cells / Q000276:immunology
D008351:Mannans; D011948:Receptors, Antigen, T-Cell; D054596:Protein Tyrosine Phosphatase, Non-Receptor Type 22; C516766:Ptpn22 protein, mouse