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.
Notch-RBP-J signaling plays an essential role in the maintenance of myeloid homeostasis. However, its role in monocyte cell fate decisions is not fully understood. Here, we showed that conditional deletion of transcription factor RBP-J in myeloid cells resulted in marked accumulation of blood Ly6Clo monocytes that highly expressed chemokine receptor CCR2. Bone marrow transplantation and parabiosis experiments revealed a cell-intrinsic requirement of RBP-J for controlling blood Ly6CloCCR2hi monocytes. RBP-J-deficient Ly6Clo monocytes exhibited enhanced capacity competing with wildtype counterparts in blood circulation. In accordance with alterations of circulating monocytes, RBP-J deficiency led to markedly increased population of lung tissues with Ly6Clo monocytes and CD16.2+ interstitial macrophages. Furthermore, RBP-J deficiency-associated phenotypes could be genetically corrected by further deleting Ccr2 in myeloid cells. These results demonstrate that RBP-J functions as a crucial regulator of blood Ly6Clo monocytes and thus derived lung-resident myeloid populations, at least in part through regulation of CCR2.
T cells are crucial for efficient antigen-specific immune responses and thus their migration within the body, to inflamed tissues from circulating blood or to secondary lymphoid organs, plays a very critical role. T cell extravasation in inflamed tissues depends on chemotactic cues and interaction between endothelial adhesion molecules and cellular integrins. A migrating T cell is expected to sense diverse external and membrane-intrinsic mechano-physical cues, but molecular mechanisms of such mechanosensing in cell migration are not established. We explored if the professional mechanosensor Piezo1 plays any role during integrin-dependent chemotaxis of human T cells. We found that deficiency of Piezo1 in human T cells interfered with integrin-dependent cellular motility on ICAM-1-coated surface. Piezo1 recruitment at the leading edge of moving T cells is dependent on and follows focal adhesion formation at the leading edge and local increase in membrane tension upon chemokine receptor activation. Piezo1 recruitment and activation, followed by calcium influx and calpain activation, in turn, are crucial for the integrin LFA1 (CD11a/CD18) recruitment at the leading edge of the chemotactic human T cells. Thus, we find that Piezo1 activation in response to local mechanical cues constitutes a membrane-intrinsic component of the ‘outside-in’ signaling in human T cells, migrating in response to chemokines, that mediates integrin recruitment to the leading edge.