The interferon-rich skin environment regulates Langerhans cell ADAM17 to promote photosensitivity in lupus
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ABSTRACT: The autoimmune disease lupus erythematosus (lupus) is characterized in part by photosensitivity, where patients can develop inflammatory skin lesions with even ambient ultraviolet radiation (UVR) exposure. Evidence points to a role for type I interferon (IFN-I) in photosensitivity, but mechanistic understanding remains limited. We have shown that photosensitivity in lupus models is at least in part attributable to Langerhans cell (LC) dysfunction. Healthy LCs limit photosensitivity via a disintegrin and metalloprotease 17 (ADAM17), a sheddase that normally limits UVR-induced skin inflammation by releasing soluble epidermal growth factor receptor (EGFR) ligands to support keratinocyte survival. On the other hand, LCs from lesional and even non-lesional lupus model skin show reduced ADAM17 activity and mRNA expression. Non-lesional human lupus skin also showed evidence of LC dysfunction, and, here, we asked how the lupus skin environment contributes to this dysfunction. We show that non-lesional skin in human CLE and multiple photosensitive lupus models share gene expression patterns consistent with a high IFN environment and LC dysfunction. IFN-I inhibits murine and human LC ADAM17 activity, and anti-IFNAR1 in lupus models restores LC ADAM17 function and reduces photosensitivity in EGFR and LC ADAM17-dependent manners. Reactive oxygen species (ROS) are a mediator of ADAM17 activity, and we show that lupus models have reduced UVR-induced LC ROS generation that is restored by anti-IFNAR1. Our findings suggest shared pathogenic mechanisms of photosensitivity in human and murine lupus skin and a model whereby the IFN-I-rich microenvironment in non-lesional lupus skin inhibits UVR-induced ADAM17 activity, predisposing to photosensitivity. Our data also suggest that the beneficial effects of the recently FDA-approved anifrolumab (anti-IFNAR1) on human lupus skin could act in part by restoring LC function.
Project description:The autoimmune disease lupus erythematosus (lupus) is characterized in part by photosensitivity, where patients can develop inflammatory skin lesions with even ambient ultraviolet radiation (UVR) exposure. Evidence points to a role for type I interferon (IFN-I) in photosensitivity, but mechanistic understanding remains limited. We have shown that photosensitivity in lupus models is at least in part attributable to Langerhans cell (LC) dysfunction. Healthy LCs limit photosensitivity via a disintegrin and metalloprotease 17 (ADAM17), a sheddase that normally limits UVR-induced skin inflammation by releasing soluble epidermal growth factor receptor (EGFR) ligands to support keratinocyte survival. On the other hand, LCs from lesional and even non-lesional lupus model skin show reduced ADAM17 activity and mRNA expression. Non-lesional human lupus skin also showed evidence of LC dysfunction, and, here, we asked how the lupus skin environment contributes to this dysfunction. We show that non-lesional skin in human CLE and multiple photosensitive lupus models share gene expression patterns consistent with a high IFN environment and LC dysfunction. IFN-I inhibits murine and human LC ADAM17 activity, and anti-IFNAR1 in lupus models restores LC ADAM17 function and reduces photosensitivity in EGFR and LC ADAM17-dependent manners. Reactive oxygen species (ROS) are a mediator of ADAM17 activity, and we show that lupus models have reduced UVR-induced LC ROS generation that is restored by anti-IFNAR1. Our findings suggest shared pathogenic mechanisms of photosensitivity in human and murine lupus skin and a model whereby the IFN-I-rich microenvironment in non-lesional lupus skin inhibits UVR-induced ADAM17 activity, predisposing to photosensitivity. Our data also suggest that the beneficial effects of the recently FDA-approved anifrolumab (anti-IFNAR1) on human lupus skin could act in part by restoring LC function.
Project description:The autoimmune disease lupus erythematosus (lupus) is characterized in part by photosensitivity, where patients can develop inflammatory skin lesions with even ambient ultraviolet radiation (UVR) exposure. Evidence points to a role for type I interferon (IFN-I) in photosensitivity, but mechanistic understanding remains limited. We have shown that photosensitivity in lupus models is at least in part attributable to Langerhans cell (LC) dysfunction. Healthy LCs limit photosensitivity via a disintegrin and metalloprotease 17 (ADAM17), a sheddase that normally limits UVR-induced skin inflammation by releasing soluble epidermal growth factor receptor (EGFR) ligands to support keratinocyte survival. On the other hand, LCs from lesional and even non-lesional lupus model skin show reduced ADAM17 activity and mRNA expression. Non-lesional human lupus skin also showed evidence of LC dysfunction, and, here, we asked how the lupus skin environment contributes to this dysfunction. We show that non-lesional skin in human CLE and multiple photosensitive lupus models share gene expression patterns consistent with a high IFN environment and LC dysfunction. IFN-I inhibits murine and human LC ADAM17 activity, and anti-IFNAR1 in lupus models restores LC ADAM17 function and reduces photosensitivity in EGFR and LC ADAM17-dependent manners. Reactive oxygen species (ROS) are a mediator of ADAM17 activity, and we show that lupus models have reduced UVR-induced LC ROS generation that is restored by anti-IFNAR1. Our findings suggest shared pathogenic mechanisms of photosensitivity in human and murine lupus skin and a model whereby the IFN-I-rich microenvironment in non-lesional lupus skin inhibits UVR-induced ADAM17 activity, predisposing to photosensitivity. Our data also suggest that the beneficial effects of the recently FDA-approved anifrolumab (anti-IFNAR1) on human lupus skin could act in part by restoring LC function.
Project description:Skin inflammation and photosensitivity are common in lupus erythematosus (LE) patients, and Ultraviolet (UV) light is a known trigger of skin and possibly systemic inflammation in systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE) patients. Type I interferons (IFN) are upregulated in LE skin after UV exposure, however, the mechanisms to explain UVB-induced inflammation remain unclear. Here we performed RNA-seq to HaCat cells with UVB irradiation to characterize gene expression and resolve differential responses of keratinocytes, in order to understand how the keratinocyte response contributes to the disease. Our data showed that HERVs and RIG-I pathway were activated in keratinocytes after UVB exposure and indicate that RIG-I pathway and HERVs are involved in proinflammatory by activating the I-IFN pathway, which provide a novel insight into how UVB promotes and aggravate skin lesion of LE patients.
Project description:Skin inflammation and photosensitivity are common manifestations of cutaneous and systemic lupus erythematosus (SLE), yet the underlying mechanisms are poorly understood. Non-lesional SLE skin exhibits increased UVB-driven cell death that persists in culture, supporting a potential role for epigenetic modifications to sustain this phenotype. We thus examined differential DNA methylation of non-lesional SLE vs. healthy control keratinocytes (KC) and identified Hippo signaling as the top significantly differentially methylated pathway, likely driven by hypomethylation of WWC1, a scaffold protein and Hippo pathway regulator. Analysis of non-lesional SLE skin biopsies and SLE keratinocytes in culture confirmed WWC1 overexpression that led to enhanced phosphorylation of YAP resulting in a pro-apoptotic transcriptional profile reflective of decreased YAP/TEAD transcriptional coactivation. Functional studies of UV-mediated apoptosis confirmed a regulatory role for YAP/TEAD interactions, and blockade of overactive Hippo signaling via a LATS1/2 inhibitor abrogated enhanced apoptosis in SLE KCs. Thus, our work identifies a novel mechanistic paradigm in SLE KCs in which aberrant UVB-apoptosis is driven by Hippo signaling via promotion of YAP phosphorylation and restriction of YAP coactivation of TEAD transcriptional activity. Hippo modulation may be a novel target for photosensitivity in SLE and CLE.
Project description:Single-cell RNA and spatial sequencing of lesional and non-lesional cutaneous lupus skin compared to healthy controls. The study includes 12 single-cell samples (cutaneous lupus patients with non-lesional (5) and lesional (4) skin biopsies with healthy controls (3)) and 4 spatial transcriptomics samples (cutaneous lupus patient pre/post-Anifrolumab treatment, 1 additional CLE patient, and 1 healthy control).
Project description:Cutaneous lupus erythematosus (CLE) is a disfiguring and poorly understood condition frequently associated with systemic lupus. Studies to date suggest that non-lesional keratinocytes play a role in disease predisposition, but this has not been investigated in a comprehensive manner or in the context of other cell populations. To investigate CLE immunopathogenesis, normal-appearing skin, lesional skin, and circulating immune cells from lupus patients were analyzed via integrated single-cell RNA-sequencing and spatial-seq. We demonstrate that normal-appearing skin of lupus patients represents a type I interferon-rich, ‘prelesional’ environment that skews gene transcription in all major skin cell types and dramatically distorts cell-cell communication. Further, we show that lupus-enriched CD16+ dendritic cells undergo robust interferon education in the skin, thereby gaining pro-inflammatory phenotypes. Together, our data provide a comprehensive characterization of lesional and non-lesional skin in lupus and identify a role for skin education of CD16+ dendritic cells in CLE pathogenesis.
Project description:Cutaneous lichen planus (LP) is a chronic inflammatory skin disease histologically characterized by an interface dermatitis with lymphocyte infiltration and keratinocyte cell-death. Previous studies suggest that LP inflammation is dominated by a type I immune response involving IFN-g but its pathogenesis remains not fully elucidated yet. To investigate the inflammatory mechanisms underlying LP, we performed single-cell RNA sequencing on LP compared with healthy control skins. We demonstrate that lesional skin from patient with LP is imprinted by a type I interferon (IFN-I)-rich environment, involving all the main skin cell components. While all immune cells are imbued with this interferon signature, we highlight unique subsets of inflammatory keratinocytes and fibroblasts highly influenced by IFN-I near the epidermis-dermis junction. We also show a unique CD8+CXCL13+ T cell population exhibiting cytotoxic and epidermis-homing markers together with an enrichment in inflammatory CD16+ myeloid cells in LP skin. Herein, we illustrate that IFN-I education on all major skin cell types and particularly in keratinocytes drives the interface dermatitis reaction, thus orchestrating the cross-talk between immune and stromal cells in LP skin. Last, we suggest the effectiveness of targeting the common IFN-I receptor, IFNAR1, to switch off the activation of inflammatory pathways in an ex-vivo model of LP skin and in on patient with lupus lichen skin lesions. Together, our data provide a comprehensive characterization of LP immunopathogenesis and demonstrate the strong involvement of IFN-I in its inflammatory landscape, providing arguments for the therapeutic use of drugs targeting IFN-I pathway in patients with LP.