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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Brownlie, Rebecca J, et al.
(författare)
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Distinct cell-specific control of autoimmunity and infection by FcgammaRIIb.
- 2008
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Ingår i: The Journal of experimental medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 205:4, s. 883-95
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Tidskriftsartikel (refereegranskat)abstract
- FcgammaRIIb is an inhibitory Fc receptor expressed on B cells and myeloid cells. It is important in controlling responses to infection, and reduced expression or function predisposes to autoimmunity. To determine if increased expression of FcgammaRIIb can modulate these processes, we created transgenic mice overexpressing FcgammaRIIb on B cells or macrophages. Overexpression of FcgammaRIIb on B cells reduced the immunoglobulin G component of T-dependent immune responses, led to early resolution of collagen-induced arthritis (CIA), and reduced spontaneous systemic lupus erythematosus (SLE). In contrast, overexpression on macrophages had no effect on immune responses, CIA, or SLE but increased mortality after Streptococcus pneumoniae infection. These results help define the role of FcgammaRIIb in immune responses, demonstrate the contrasting roles played by FcgammaRIIb on B cells and macrophages in the control of infection and autoimmunity, and emphasize the therapeutic potential for modulation of FcgammaRIIb expression on B cells in inflammatory and autoimmune disease.
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| 3. |
- Burn, Garth L., et al.
(författare)
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Superresolution imaging of the cytoplasmic phosphatase PTPN22 links integrin-mediated T cell adhesion with autoimmunity
- 2016
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Ingår i: Science Signaling. - : American Association for the Advancement of Science (AAAS). - 1945-0877 .- 1937-9145. ; 9:448
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Tidskriftsartikel (refereegranskat)abstract
- Integrins are heterodimeric transmembrane proteins that play a fundamental role in the migration of leukocytes to sites of infection or injury. We found that protein tyrosine phosphatase nonreceptor type 22 (PTPN22) inhibits signaling by the integrin lymphocyte function-associated antigen-1 (LFA-1) in effector T cells. PTPN22 colocalized with its substrates at the leading edge of cells migrating on surfaces coated with the LFA-1 ligand intercellular adhesion molecule-1 (ICAM-1). Knockout or knockdown of PTPN22 or expression of the autoimmune disease-associated PTPN22-R620W variant resulted in the enhanced phosphorylation of signaling molecules downstream of integrins. Superresolution imaging revealed that PTPN22-R620 (wild-type PTPN22) was present as large clusters in unstimulated T cells and that these disaggregated upon stimulation of LFA-1, enabling increased association of PTPN22 with its binding partners at the leading edge. The failure of PTPN22-R620W molecules to be retained at the leading edge led to increased LFA-1 clustering and integrin-mediated cell adhesion. Our data define a previously uncharacterized mechanism for fine-tuning integrin signaling in T cells, as well as a paradigm of auto-immunity in humans in which disease susceptibility is underpinned by inherited phosphatase mutations that perturb integrin function. 2016
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| 5. |
- Brownlie, Rebecca J., et al.
(författare)
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Lack of the Phosphatase PTPN22 Increases Adhesion of Murine Regulatory T Cells to Improve Their Immunosuppressive Function
- 2012
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Ingår i: Science Signaling. - : American Association for the Advancement of Science (AAAS). - 1937-9145 .- 1945-0877. ; 5:252, s. 87-87
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Tidskriftsartikel (refereegranskat)abstract
- The cytoplasmic phosphatase PTPN22 (protein tyrosine phosphatase nonreceptor type 22) plays a key role in regulating lymphocyte homeostasis, which ensures that the total number of lymphocytes in the periphery remains relatively constant. Mutations in PTPN22 confer an increased risk of developing autoimmune diseases; however, the precise function of PTPN22 and how mutations contribute to auto-immunity remain controversial. Loss-of-function mutations in PTPN22 are associated with increased numbers of effector T cells and autoreactive B cells in humans and mice; however, the complete absence of PTPN22 in mice does not result in spontaneous autoimmunity. We found that PTPN22 was a key regulator of regulatory T cell (T-reg) function that fine-tuned the signaling of the T cell receptor and integrins. PTPN22(-/-) T-regs were more effective at immunosuppression than were wild-type T-regs, and they suppressed the activity of PTPN22(-/-) effector T cells, preventing autoimmunity. Compared to wildtype T-regs, PTPN22(-/-) T-regs produced increased amounts of the immunosuppressive cytokine interleukin-10 and had enhanced adhesive properties mediated by the integrin lymphocyte function-associated antigen-1, processes that are critical for T-reg function. This previously undiscovered role of PTPN22 in regulating integrin signaling and T-reg function suggests that PTPN22 may be a useful therapeutic target for manipulating T-reg function in human disease.
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