An Open-Label, Uncontrolled, Single-Arm Clinical Trial of Tofacitinib, an Oral JAK1 and JAK3 Kinase Inhibitor, in Chinese Patients with Keloid.

BACKGROUND: The keloid treatment is still a thorny and complicated clinical problem, especially in multiple keloids induced by wound, severe burn, ethnic background or cultural behaviors, or unexplained skin healing. Mainstream treatments have limited efficacy in treating multiple keloids. As no oral treatment with painlessness and convenience is available, oral treatment strategies should be formulated. OBJECTIVES: This study aimed to investigate the efficacy and therapeutic mechanism of oral tofacitinib in keloid patients. METHODS: We recruited the 7 patients with keloid scars and prescribed 5 mg of tofacitinib twice a day orally with a maximum follow-up of 12 weeks. The Patient and Observer Scar Assessment Scale (POSAS), the Vancouver scar scale (VSS), ANTERA 3D camera, and the DUB Skin Scanner 75 were used to assess the characteristics of the lesion. Immunohistochemistry was performed to evaluate collagen synthesis, proliferation, and relative molecular pathways. Moreover, the effects of tofacitinib were assessed on keloid fibroblast in vitro. RESULTS: After 12 weeks of oral tofacitinib, significant improvement in POSAS, VSS, and Dermatology Life Quality Index (DLQI) scores was observed (p < 0.05). The volume, lesion height, and dermis thickness of the keloid decreased (p < 0.05). Moreover, significant decreases in the expression of collagen I, Ki67, p-STAT 3, and p-SMAD2 were observed after 12 weeks of administration. In vitro experiments suggested that tofacitinib treatment inhibits fibroblast proliferation and collagen I synthesis via suppression of STAT3 and SMAD2 pathway. CONCLUSION: Tofacitinib, a new candidate oral drug for keloid, could reduce keloid lesion volume by inhibiting collagen synthesis and inhibiting fibroblast proliferation, and alleviate itch and pain to obtain a better life quality.

Relief of Extracellular Matrix Deposition Repression by Downregulation of IRF1-Mediated TWEAK/Fn14 Signaling in Keloids.

Keloids represent a fibrotic disorder characterized by the excessive deposition of extracellular matrix (ECM). However, the mechanisms through which ECM deposition in keloids is regulated remain elusive. In this study, we found that the expression of both TWEAK and its cognate receptor Fn14 was significantly downregulated in keloids and that TWEAK/Fn14 signaling repressed the expression of ECM-related genes in keloid fibroblasts. The IRF1 gene was essential for this repression, and the TWEAK/Fn14 downstream transcription factor p65 directly bound to the promoter of the IRF1 gene and induced its expression. Furthermore, in patients with keloid, the expression of TWEAK and Fn14 was negatively correlated with that of ECM genes and positively correlated with that of IRF1. These observations indicate that relief of TWEAK/Fn14/IRF1-mediated ECM deposition repression contributes to keloid pathogenesis, and the identified mechanism and related molecules provide potential targets for keloid treatment in the future.

Risk single-nucleotide polymorphism-mediated enhancer-promoter interaction drives keloids through long noncoding RNA down expressed in keloids.

BACKGROUND: Keloids represent one extreme of aberrant dermal wound healing and are characterized by fibroblast hyperproliferation and excessive deposition of extracellular matrix. Genetics is a major factor for predisposition to keloids and genome-wide association study has identified a single-nucleotide polymorphism (SNP) rs873549 at 1q41 as a susceptibility locus. The SNP rs873549, and the SNPs in strong linkage disequilibrium (LD) with rs873549, may be involved in keloid development. However, the functional significance of these SNPs in keloid pathogenesis remains elusive. OBJECTIVES: To investigate the function and mechanism of SNP rs873549 and the SNPs in strong LD with rs873549 in keloids. METHODS: SNPs in strong LD with rs873549 were analysed using Haploview. The expression levels of the genes near the susceptibility locus were analysed using quantitative real-time polymerase chain reaction. The interaction between rs1348270-containing enhancer and the long noncoding RNA down expressed in keloids (DEIK) (formerly RP11-400N13.1) promoter in fibroblasts was investigated using chromosome conformation capture. The enhancer activity of the rs1348270 locus was evaluated using luciferase reporter assay. Knockdown experiments were used to explore the function of DEIK in keloids. RNA-Seq was performed to investigate the mechanism by which DEIK regulates the expression of collagens POSTN and COMP. RESULTS: rs1348270, an enhancer-located SNP in strong LD with rs873549, mediated looping with the promoter of DEIK. The risk variant was associated with decreased enhancer-promoter interaction and DEIK down-expression in keloids. Mechanistically, downregulation of DEIK increased the expression of collagens POSTN and COMP through upregulating BMP2. Furthermore, correlation analysis revealed that DEIK expression was inversely correlated with BMP2, POSTN and COMP expression in both keloid and normal fibroblasts. CONCLUSIONS: Our findings suggest that the risk variant rs1348270 is located in an enhancer and is associated with the downregulation of DEIK in keloids, and that downregulation of DEIK increases the expression of collagens POSTN and COMP through BMP2 in keloid fibroblasts. These findings will help to provide a more thorough understanding of the role played by genetic factors in keloid development and may lead to new strategies for screening and therapy in keloid-susceptible populations.

Single-cell RNA-seq reveals fibroblast heterogeneity and increased mesenchymal fibroblasts in human fibrotic skin diseases.

Fibrotic skin disease represents a major global healthcare burden, characterized by fibroblast hyperproliferation and excessive accumulation of extracellular matrix. Fibroblasts are found to be heterogeneous in multiple fibrotic diseases, but fibroblast heterogeneity in fibrotic skin diseases is not well characterized. In this study, we explore fibroblast heterogeneity in keloid, a paradigm of fibrotic skin diseases, by using single-cell RNA-seq. Our results indicate that keloid fibroblasts can be divided into 4 subpopulations: secretory-papillary, secretory-reticular, mesenchymal and pro-inflammatory. Interestingly, the percentage of mesenchymal fibroblast subpopulation is significantly increased in keloid compared to normal scar. Functional studies indicate that mesenchymal fibroblasts are crucial for collagen overexpression in keloid. Increased mesenchymal fibroblast subpopulation is also found in another fibrotic skin disease, scleroderma, suggesting this is a broad mechanism for skin fibrosis. These findings will help us better understand skin fibrotic pathogenesis, and provide potential targets for fibrotic disease therapies.

TRAF4 Promotes Fibroblast Proliferation in Keloids by Destabilizing p53 via Interacting with the Deubiquitinase USP10.

Keloids represent one extreme of aberrant dermal wound healing. One of the important characteristics of keloids is uncontrolled fibroblasts proliferation. However, the mechanism of excessive proliferation of fibroblasts in keloids remains elusive. In this study, we demonstrated that TRAF4 was highly expressed in keloid fibroblasts and promoted fibroproliferation. We investigated the underlying molecular mechanism and found that TRAF4 suppressed the p53 pathway independent of its E3 ubiquitin ligase activity. Specifically, TRAF4 interacted with the deubiquitinase USP10 and blocked the access of p53 to USP10, resulting in p53 destabilization. Knockdown of p53 rescued cell proliferation in TRAF4-knockdown keloid fibroblasts, suggesting that the regulation of proliferation by TRAF4 in keloids relied on p53. Furthermore, in keloid patient samples, TRAF4 expression was inversely correlated with p53-p21 signaling activity. These findings help to elucidate the mechanisms underlying keloid development and indicate that blocking TRAF4 could represent a potential strategy for keloid therapy in the future.