To investigate how the CARD14E138A psoriasis-associated mutation induces skin inflammation, a knock-in mouse strain was generated that allows tamoxifen-induced expression of the homologous Card14E138A mutation from the endogenous mouse Card14 locus. Heterozygous expression of CARD14E138A rapidly induced skin acanthosis, immune cell infiltration and expression of psoriasis-associated pro-inflammatory genes. Homozygous expression of CARD14E138A induced more extensive skin inflammation and a severe systemic disease involving infiltration of myeloid cells in multiple organs, temperature reduction, weight loss and organ failure. This severe phenotype resembled acute exacerbations of generalized pustular psoriasis (GPP), a rare form of psoriasis that can be caused by CARD14 mutations in patients. CARD14E138A-induced skin inflammation and systemic disease were independent of adaptive immune cells, ameliorated by blocking TNF and induced by CARD14E138A signalling only in keratinocytes. These results suggest that anti-inflammatory therapies specifically targeting keratinocytes, rather than systemic biologicals, might be effective for GPP treatment early in disease progression.
The RNA-Seq data generated in this article was deposited in the GEO repository (GSE149880).
Expression analysis of WT or Card14E138A ears 5 days and 1 month after injecton of tamoxifen.NCBI Gene Expression Omnibus, GSE149880.
A spatio-temporal characterization of the transcriptional landscape of epidermal developmentNCBI Gene Expression Omnibus, GSE75931.
RNA-sequencing transcriptome profiling of normal human keratinocytes differentiationNCBI Gene Expression Omnibus, GSE73305.
A LncRNA-MAF/MAFB transcription factor network regulates epidermal differentiationNCBI Gene Expression Omnibus, GSE52954.
- Joan Manils
- Louise V Webb
- Julia Janzen
- Stefan Boeing
- Steven C Ley
- Joan Manils
- Louise V Webb
- Ashleigh Howes
- Anne M Bowcock
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: Mice were bred and maintained under specific pathogen-free conditions at the Francis Crick 787 Institute. Experiments were performed in accordance with UK Home Office regulations and endorsed by the Francis Crick Institute Animal Welfare and Ethical Review Body under the Procedure Project Licence 70/8819. Rosa26CreERT2 (Seibler et al., 2003), Krt14CreERT2 (Hong et al., 2004), VillinCreERT2 (el Marjou et al., 2004) and Rag1-/- (Spanopoulou et al., 1994) mouse lines have been described previously.
- Carla V Rothlin, Yale School of Medicine, United States
© 2020, Manils et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Chronic autoimmune diseases are associated with mutations in PTPN22, a modifier of T cell receptor (TCR) signaling. As with all protein tyrosine phosphatases, the activity of PTPN22 is redox regulated, but if or how such regulation can modulate inflammatory pathways in vivo is not known. To determine this, we created a mouse with a cysteine-to-serine mutation at position 129 in PTPN22 (C129S), a residue proposed to alter the redox regulatory properties of PTPN22 by forming a disulfide with the catalytic C227 residue. The C129S mutant mouse showed a stronger T-cell-dependent inflammatory response and development of T-cell-dependent autoimmune arthritis due to enhanced TCR signaling and activation of T cells, an effect neutralized by a mutation in Ncf1, a component of the NOX2 complex. Activity assays with purified proteins suggest that the functional results can be explained by an increased sensitivity to oxidation of the C129S mutated PTPN22 protein. We also observed that the disulfide of native PTPN22 can be directly reduced by the thioredoxin system, while the C129S mutant lacking this disulfide was less amenable to reductive reactivation. In conclusion, we show that PTPN22 functionally interacts with Ncf1 and is regulated by oxidation via the noncatalytic C129 residue and oxidation-prone PTPN22 leads to increased severity in the development of T-cell-dependent autoimmunity.
The oxidative state of a critical cysteine residue determines the enzymatic activity of a phosphatase involved in T-cell immune responses.