CXCL10 secreted by SPRY1-deficient epidermal keratinocytes fuels joint inflammation in psoriatic arthritis via CD14 signaling
Fan Xu, Ying-Zhe Cui, Xing-Yu Yang, Yu-Xin Zheng, Xi-Bei Chen, Hao Zhou, Zhao-Yuan Wang, Yuan Zhou, Yi Lu, Ying-Ying Li, Li-Ran Ye, Ni-Chang Fu, Si-Qi Chen, Xue-Yan Chen, Min Zheng, Yong Yang, Xiao-Yong Man
Fan Xu, Ying-Zhe Cui, Xing-Yu Yang, Yu-Xin Zheng, Xi-Bei Chen, Hao Zhou, Zhao-Yuan Wang, Yuan Zhou, Yi Lu, Ying-Ying Li, Li-Ran Ye, Ni-Chang Fu, Si-Qi Chen, Xue-Yan Chen, Min Zheng, Yong Yang, Xiao-Yong Man
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Research Article Dermatology Immunology

CXCL10 secreted by SPRY1-deficient epidermal keratinocytes fuels joint inflammation in psoriatic arthritis via CD14 signaling

Abstract

Psoriatic arthritis (PsA) is a multifaceted, chronic inflammatory disease affecting the skin, joints, and entheses, and it is a major comorbidity of psoriasis. Most patients with PsA present with psoriasis before articular involvement; however, the molecular and cellular mechanisms underlying the link between cutaneous psoriasis and PsA are poorly understood. Here, we found that epidermis-specific SPRY1-deficient mice spontaneously developed PsA-like inflammation involving both the skin and joints. Excessive CXCL10 was secreted by SPRY1-deficient epidermal keratinocytes through enhanced activation of JAK1/2/STAT1 signaling, and CXCL10 blockade attenuated PsA-like inflammation. Of note, CXCL10 was found to bind to CD14, but not CXCR3, to promote the TNF-α production of periarticular CD14hi macrophages via PI3K/AKT and NF-κB signaling pathways. Collectively, this study reveals that SPRY1 deficiency in the epidermis is sufficient to drive both skin and joint inflammation, and it identifies keratinocyte-derived CXCL10 and periarticular CD14hi macrophages as critical links in the skin-joint crosstalk leading to PsA. This keratinocyte SPRY1/CXCL10/periarticular CD14hi macrophage/TNF-α axis provides valuable insights into the mechanisms underlying the transition from psoriasis to PsA and suggests potential therapeutic targets for preventing this progression.

Authors

Fan Xu, Ying-Zhe Cui, Xing-Yu Yang, Yu-Xin Zheng, Xi-Bei Chen, Hao Zhou, Zhao-Yuan Wang, Yuan Zhou, Yi Lu, Ying-Ying Li, Li-Ran Ye, Ni-Chang Fu, Si-Qi Chen, Xue-Yan Chen, Min Zheng, Yong Yang, Xiao-Yong Man

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Figure 7

Keratinocyte-derived CXCL10 binds to CD14 and mediates the proinflammatory response in periarticular CD14hi macrophages.

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Keratinocyte-derived CXCL10 binds to CD14 and mediates the proinflammato...
(A and B) Flow cytometric analysis of TNF-α, IL-1β, and CD86 expression in RAW264.7 cells treated with blank keratinocyte medium plus IgG, control KC-CM plus IgG, Spry1-cKO KC-CM plus IgG, and Spry1-cKO KC-CM plus 2 μg/mL anti-CXCL10 antibody for 24 hours (A), or treated with or without 100 ng/mL recombinant murine CXCL10 for 24 hours (B), followed by incubation with 50 ng/mL LPS and BFA for 6 hours (n = 3). (C) Dot plots showing scaled expression (scRNA-Seq) of potential CXCL10 receptor genes mouse periarticular CD14hi macrophages. (D) Co-immunoprecipitation of TLR2, TLR4, CD14, and CXCL10 in RAW264.7 cells after recombinant murine CXCL10 treatment. (E) Immunoprecipitation of recombinant murine CD14 and CXCL10 proteins. (F) Confocal images of CD14 and CXCL10 colocalization in RAW264.7 cells after treatment with recombinant murine CXCL10. Boxed areas are magnified below. Scale bar: 100 μm. (G) Optimized binding mode with the lowest binding energy generated by HDOCK, and key residues for interaction between mouse CXCL10 and CD14. Boxed areas are magnified below. Hydrogen bonds are shown as yellow dashed lines and salt bridges as red dashed lines. (H) Immunoblotting analysis of protein levels associated with PI3K/AKT and NF-κB signaling pathways in RAW264.7 cells treated with NC or siCd14, followed by recombinant murine CXCL10 stimulation. (I) Flow cytometric analysis of CD14, CD86, TNF-α, and IL-1β expression in RAW264.7 cells treated with NC or siCd14, followed by recombinant murine CXCL10 stimulation and subsequent incubation with LPS and BFA (n = 3). (J) TSNE plots of 8 immune cell clusters in synovial fluid (SF) from PsA patients (GSE161500). (K) TSNE plots showing CD14 and CXCR3 expression across clusters defined in J. (L) TSNE plots showing single cell–level enrichment of inflammatory response and TNF-α signaling via NF-κB signatures in all immune clusters defined in J by GSVA. (M and N) GSVA for pathway enrichment of CD14+ versus CD14– macrophages (M) and CD14+ macrophages versus CXCR3+ T cells (N) in PsA SF (GSE161500). Data are shown as mean ± SEM. P values determined using 1-way ANOVA (A) and 2-tailed unpaired Student’s t test (B and I). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001.