IL-13RA2 downregulation in fibroblasts promotes keloid fibrosis via JAK/STAT6 activation

Identification of novel immune-related signatures for keloid diagnosis and treatment: insights from integrated bulk RNA-seq and scRNA-seq analysis

BACKGROUND

Keloid is a disease characterized by proliferation of fibrous tissue after the healing of skin tissue, which seriously affects the daily life of patients. However, the clinical treatment of keloids still has limitations, that is, it is not effective in controlling keloids, resulting in a high recurrence rate. Thus, it is urgent to identify new signatures to improve the diagnosis and treatment of keloids.

METHOD

Bulk RNA seq and scRNA seq data were downloaded from the GEO database. First, we used WGCNA and MEGENA to co-identify keloid/immune-related DEGs. Subsequently, we used three machine learning algorithms (Randomforest, SVM-RFE, and LASSO) to identify hub immune-related genes of keloid (KHIGs) and investigated the heterogeneous expression of KHIGs during fibroblast subpopulation differentiation using scRNA-seq. Finally, we used HE and Masson staining, quantitative reverse transcription-PCR, western blotting, immunohistochemical, and Immunofluorescent assay to investigate the dysregulated expression and the mechanism of retinoic acid in keloids.

RESULTS

In the present study, we identified PTGFR, RBP5, and LIF as KHIGs and validated their diagnostic performance. Subsequently, we constructed a novel artificial neural network molecular diagnostic model based on the transcriptome pattern of KHIGs, which is expected to break through the current dilemma faced by molecular diagnosis of keloids in the clinic. Meanwhile, the constructed IG score can also effectively predict keloid risk, which provides a new strategy for keloid prevention. Additionally, we observed that KHIGs were also heterogeneously expressed in the constructed differentiation trajectories of fibroblast subtypes, which may affect the differentiation of fibroblast subtypes and thus lead to dysregulation of the immune microenvironment in keloids. Finally, we found that retinoic acid may treat or alleviate keloids by inhibiting RBP5 to differentiate pro-inflammatory fibroblasts (PIF) to mesenchymal fibroblasts (MF), which further reduces collagen secretion.

CONCLUSION

In summary, the present study provides novel immune signatures (PTGFR, RBP5, and LIF) for keloid diagnosis and treatment, and identifies retinoic acid as potential anti-keloid drugs. More importantly, we provide a new perspective for understanding the interactions between different fibroblast subtypes in keloids and the remodeling of their immune microenvironment.

PFDA promotes cancer metastasis through macrophage M2 polarization mediated by Wnt/β-catenin signaling

Perfluoroundecanoic acid (PFDA) is extensively utilized in the textile and food processing industries and may have a tumor-promoting effect by modulating the tumor microenvironment. Macrophages play crucial roles in tumor microenvironment as key regulators of tumor immunity. However, further investigation is needed to elucidate how PFDA interacts with macrophages and contributes to tumor progression. In this study, we treated the macrophage cell line RAW264.7 with various concentrations of PFDA and found that RAW264.7 transitioned into an M2 tumor-promoting phenotype. Through bioinformatic analysis and subsequent verification of molecular assays, we uncovered that PFDA could activate β-catenin and enhance its nuclear translocation. Additionally, it was also observed that inhibiting β-catenin nuclear translocation partly attenuated RAW264.7 M2 polarization induced by PFDA. The conditioned medium derived from PFDA-pretreated RAW264.7 cells significantly promoted the migration and invasion abilities of human ovarian cancer cells. Furthermore, in vivo studies corroborated that PFDA-pretreated RAW264.7 could promote tumor metastasis, which could be mitigated by pretreatment with the β-catenin inhibitor ICG001. In conclusion, our study demonstrated that PFDA could promote cancer metastasis through regulating macrophage M2 polarization in a Wnt/β-catenin-dependent manner.

Low-Frequency Ultrasound Sensitive Piezo1 Channels Regulate Keloid-Related Characteristics of Fibroblasts

Keloids are benign fibroproliferative tumors that severely diminish the quality of life due to discomfort, dysfunction, and disfigurement. Recently, ultrasound technology as a noninvasive adjuvant therapy is developed to optimize treatment protocols. However, the biophysical mechanisms have not yet been fully elucidated. Here, it is proposed that piezo-type mechanosensitive ion channel component 1 (Piezo1) plays an important role in low-frequency sonophoresis (LFS) induced mechanical transduction pathways that trigger downstream cellular signaling processes. It is demonstrated that patient-derived primary keloid fibroblasts (PKF), NIH 3T3, and HFF-1 cell migration are inhibited, and PKF apoptosis is significantly increased by LFS stimulation. And the effects of LFS is diminished by the application of GsMTx-4, the selective inhibitor of Piezo1, and the knockdown of Piezo1. More importantly, the effects of LFS can be imitated by Yoda1, an agonist of Piezo1 channels. Establishing a patient-derived xenograft keloid implantation mouse model further verified these results, as LFS significantly decreased the volume and weight of the keloids. Moreover, blocking the Piezo1 channel impaired the effectiveness of LFS treatment. These results suggest that LFS inhibits the malignant characteristics of keloids by activating the Piezo1 channel, thus providing a theoretical basis for improving the clinical treatment of keloids.

Macrophage phenotype is determinant for fibrosis development in keloid disease

Keloid refers to a fibroproliferative disorder characterized by an accumulation of extracellular matrix (ECM) components at the dermis level, overgrowth beyond initial wound, and formation of tumor-like nodule areas. Treating keloid is still an unmet clinical need and the lack of an efficient therapy is clearly related to limited knowledge about keloid etiology, despite the growing interest of the scientific community in this pathology. In past decades, keloids were often studied in vitro through the sole prism of fibroblasts considered as the major effector of ECM deposition. Nevertheless, development of keloids results from cross-interactions of keloid fibroblasts (KFs) and their surrounding microenvironment, including immune cells such as macrophages. Our study aimed to evaluate the effect of M1 and M2 monocyte-derived macrophages on KFs in vitro. We focused on the effects of the macrophage secretome on fibrosis-related criteria in KFs, including proliferation, migration, differentiation, and ECM synthesis. First, we demonstrated that M2-like macrophages enhanced the fibrogenic profile of KFs in culture. Then, we surprisingly founded that M1-like macrophages can have an anti-fibrogenic effect on KFs, even in a pro-fibrotic environment. These results demonstrate, for the first time, that M1 and M2 macrophage subsets differentially impact the fibrotic fate of KFs in vitro, and suggest that restoring the M1/M2 balance to favor M1 in keloids could be an efficient therapeutic lever to prevent or treat keloid fibrosis.

Moscatilin inhibits vascular calcification by activating IL13RA2-dependent inhibition of STAT3 and attenuating the WNT3/β-catenin signalling pathway

INTRODUCTION

Vascular calcification, a devastating vascular complication accompanying atherosclerotic cardiovascular disease and chronic kidney disease, increases the incidence of adverse cardiovascular events and compromises the efficacy of vascular interventions. However, effective therapeutic drugs and treatments to delay or prevent vascular calcification are lacking.

OBJECTIVES

This study was designed to test the therapeutic effects and mechanism of Moscatilin (also known as dendrophenol) from Dendrobium huoshanense (an eminent traditional Chinese medicine) in suppressing vascular calcification in vitro, ex vivo and in vivo.

METHODS

Male C57BL/6J mice (25-week-old) were subjected to nicotine and vitamin D3 (VD3) treatment to induce vascular calcification. In vitro, we established the cellular model of osteogenesis of human aortic smooth muscle cells (HASMCs) under phosphate conditions.

RESULTS

By utilizing an in-house drug screening strategy, we identified Moscatilin as a new naturally-occurring chemical entity to reduce HASMC calcium accumulation. The protective effects of Moscatilin against vascular calcification were verified in cultured HASMCs. Unbiased transcriptional profiling analysis and cellular thermal shift assay suggested that Moscatilin suppresses vascular calcification via binding to interleukin 13 receptor subunit A2 (IL13RA2) and augmenting its expression. Furthermore, IL13RA2 was reduced during HASMC osteogenesis, thus promoting the secretion of inflammatory factors via STAT3. We further validated the participation of Moscatilin-inhibited vascular calcification by the classical WNT/β-catenin pathway, among which WNT3 played a key role in this process. Moscatilin mitigated the crosstalk between WNT3/β-catenin and IL13RA2/STAT3 to reduce osteogenic differentiation of HASMCs.

CONCLUSION

This study supports the potential of Moscatilin as a new naturally-occurring candidate drug for treating vascular calcification via regulating the IL13RA2/STAT3 and WNT3/β-catenin signalling pathways.

Machine learning and single-cell transcriptome profiling reveal regulation of fibroblast activation through THBS2/TGFβ1/P-Smad2/3 signalling pathway in hypertrophic scar

Hypertrophic scar (HS) is a chronic inflammatory skin disorder characterized by excessive deposition of extracellular matrix, and the mechanisms underlying their formation remain poorly understood. We analysed scRNA-seq data from samples of normal skin and HS. Using the hdWGCNA method, key gene modules of fibroblasts in HS were identified. Non-negative matrix factorization was employed to perform subtype analysis of HS patients using these gene modules. Multiple machine learning algorithms were applied to screen and validate accurate gene signatures for identifying and predicting HS, and a convolutional neural network (CNN) based on deep learning was established and validated. Quantitative reverse transcription-polymerase chain reaction and western blotting were performed to measure mRNA and protein expression. Immunofluorescence was used for gene localization analysis, and biological features were assessed through CCK8 and wound healing assay. Single-cell sequencing revealed distinct subpopulations of fibroblasts in HS. HdWGCNA identified key gene characteristics of this population, and pseudotime analysis was conducted to investigate gene variation during fibroblast differentiation. By employing various machine learning algorithms, the gene range was narrowed down to three key genes. A CNN was trained using the expression of these key genes and immune cell infiltration, enabling diagnosis and prediction of HS. Functional experiments demonstrated that THBS2 is associated with fibroblast proliferation and migration in HS and affects the formation and development of HS through the TGFβ1/P-Smad2/3 pathway. Our study identifies unique fibroblast subpopulations closely associated with HS and provides biomarkers for the diagnosis and treatment of HS.

The Communication from Immune Cells to the Fibroblasts in Keloids: Implications for Immunotherapy

Keloids are a type of fibrotic disease characterized by excessive collagen production and extracellular matrix (ECM) deposition. The symptoms of pain and itching and frequent recurrence after treatment significantly impact the quality of life and mental health of patients. A deeper understanding of the pathogenesis of keloids is crucial for the development of an effective therapeutic approach. Fibroblasts play a central role in the pathogenesis of keloids by producing large amounts of collagen fibers. Recent evidence indicates that keloids exhibit high immune cell infiltration, and these cells secrete cytokines or growth factors to support keloid fibroblast proliferation. This article provides an update on the knowledge regarding the keloid microenvironment based on recent single-cell sequencing literature. Many inflammatory cells gathered in keloid lesions, such as macrophages, mast cells, and T lymphocytes, indicate that keloids may be an inflammatory skin disease. In this review, we focus on the communication from immune cells to the fibroblasts and the potential of immunotherapy for keloids. We hope that this review will trigger interest in investigating keloids as an inflammatory disease, which may open up new avenues for drug development by targeting immune mediators.

Macrophage polarization in tissue fibrosis

Fibrosis can occur in all major organs with relentless progress, ultimately leading to organ failure and potentially death. Unfortunately, current clinical treatments cannot prevent or reverse tissue fibrosis. Thus, new and effective antifibrotic therapeutics are urgently needed. In recent years, a growing body of research shows that macrophages are involved in fibrosis. Macrophages are highly heterogeneous, polarizing into different phenotypes. Some studies have found that regulating macrophage polarization can inhibit the development of inflammation and cancer. However, the exact mechanism of macrophage polarization in different tissue fibrosis has not been fully elucidated. This review will discuss the major signaling pathways relevant to macrophage-driven fibrosis and profibrotic macrophage polarization, the role of macrophage polarization in fibrosis of lung, kidney, liver, skin, and heart, potential therapeutics targets, and investigational drugs currently in development, and hopefully, provide a useful review for the future treatment of fibrosis.

Screening and anti-glioma activity of Chiloscyllium plagiosum anti-human IL-13Rα2 single-domain antibody

Glioblastoma is a common and fatal malignant tumour of the central nervous system, with high invasiveness. Conventional treatments for this disease, including comprehensive treatment of surgical resection combined with chemoradiotherapy, are ineffective, with low survival rate and extremely poor prognosis. Targeted therapy is promising in overcoming the difficulties in brain tumour treatment and IL-13Rα2 is a widely watched target. The development of new therapies for glioma, however, is challenged by factors, such as the unique location and immune microenvironment of gliomas. The unique advantages of single-domain antibodies (sdAbs) may provide a novel potential treatment for brain tumours. In this study, Chiloscyllium plagiosum was immunized with recombinant IL-13Rα2 protein to produce sdAb and sdAb sequences were screened by multi-omics. The targeted sdAb genes obtained were efficiently expressed in the Escherichia coli prokaryotic expression system, showing a significant binding capacity to IL-13Rα2 in vitro. The cell proliferation and migration inhibitory effects of recombinant variable domain of the new antigen receptor (VNAR) on glioma cells were detected by CCK-8 and cell scratch assays. The sdAb obtained in this study showed high in vitro activity and favourable cell proliferation inhibitory effect on glioma cells, with potential clinical application value. The present study also provides a new direction and experimental basis for the development of targeted therapies for glioma.

Interleukin-13 (IL-13)-A Pleiotropic Cytokine Involved in Wound Healing and Fibrosis

The liver, as a central metabolic organ, is systemically linked to metabolic-inflammatory diseases. In the pathogenesis of the metabolic syndrome, inflammatory and metabolic interactions between the intestine, liver, and adipose tissue lead to the progression of hepatic steatosis to metabolic-dysfunction-associated steatohepatitis (MASH) and consecutive MASH-induced fibrosis. Clinical and animal studies revealed that IL-13 might be protective in the development of MASH through both the preservation of metabolic functions and Th2-polarized inflammation in the liver and the adipose tissue. In contrast, IL-13-associated loss of mucosal gut barrier function and IL-13-associated enhanced hepatic fibrosis may contribute to the progression of MASH. However, there are only a few publications on the effect of IL-13 on metabolic diseases and possible therapies to influence them. In this review article, different aspects of IL-13-associated effects on the liver and metabolic liver diseases, which are partly contradictory, are summarized and discussed on the basis of the recent literature.

Roles of the HIF-1α pathway in the development and progression of keloids

Keloids, a pathological scar that is induced by the consequence of aberrant wound healing, is still a major global health concern for its unsatisfactory treatment outcomes. HIF-1α, a main regulator of hypoxia, mainly acts through some proteins or signaling pathways and plays important roles in a variety of biological processes. Accumulating evidence has shown that HIF-1α played a crucial role in the process of keloid formation. In this review, we attempted to summarize the current knowledge on the association between HIF-1α expression and the development and progression of keloids. Through a comprehensive analysis, the molecular mechanisms underlying HIF-1α in keloids were shown to be correlated to the proliferation of fibroblasts, angiogenesis, and collagen deposits. The affected proteins and the signaling pathways were multiple. For instance, HIF-1α was reported to promote keloids formation by enhancing angiogenesis, fibroblast proliferation, and collagen deposition through the activation of periostin PI3K/Akt, TGF-β/Smad and TLR4/MyD88/NF-κB pathway. However, the specific effects of HIF-1α on keloids keloid illnesses in clinical practice is are entirely unclear, and further studies in clinical trials are still warranted. Therefore, an in-depth understanding of the biological mechanisms of HIF-1α in keloid formation is significant to develop promising therapeutic targets for the treatment of keloids in clinical practice.