Attenuation of Dupuytren's fibrosis via targeting of the STAT1 modulated IL-13Rα1 response

C-X-C domain ligand 14-mediated stromal cell-macrophage interaction as a therapeutic target for hand dermal fibrosis

Dupuytren's contracture, a superficial dermal fibrosis, causes flexion contracture of the affected finger, impairing hand function. Specific single-nucleotide polymorphisms within genes in the Wnt signalling pathway are associated with the disease. However, the precise role of Wnt signalling dysregulation in the onset and progression of Dupuytren's contracture remains unclear. Here, using a fibrosis mouse model and clinical samples of human Dupuytren's contractures, we demonstrate that the activation of Wnt/β-catenin signalling in Tppp3-positive cells in the dermis of the paw is associated with the development of fibrosis. Fibrosis development and progression via Wnt/β-catenin signalling are closely related to stromal cell-macrophage interactions, and Wnt/β-catenin signalling activation in Tppp3-positive stromal cells causes M2 macrophage infiltration via chemokine Cxcl14, resulting in the formation of a TGF-β-expressing fibrotic niche. Inhibition of Cxcl14 mitigates fibrosis by decreasing macrophage infiltration. These findings suggest that Cxcl14-mediated stromal cell-macrophage interaction is a promising therapeutic target for Wnt/β-catenin-induced fibrosis.

NETosis promotes chronic inflammation and fibrosis in systemic lupus erythematosus and COVID-19

Pulmonary fibrosis, a serious complication of systemic lupus erythematosus (SLE) and coronavirus disease 2019 (COVID-19), leads to irreversible lung damage. However, the underlying mechanism of this condition remains unclear. In this study, we revealed the landscape of transcriptional changes in lung biopsies from individuals with SLE, COVID-19-induced pulmonary fibrosis, and idiopathic pulmonary fibrosis (IPF) using histopathology and RNA sequencing, respectively. Despite the diverse etiologies of these diseases, lung expression of matrix metalloproteinase genes in these diseases showed similar patterns. Particularly, the differentially expressed genes were significantly enriched in the pathway of neutrophil extracellular trap formation, showing similar enrichment signature between SLE and COVID-19. The abundance of Neutrophil extracellular traps (NETs) was much higher in the lungs of individuals with SLE and COVID-19 compared to those with IPF. In-depth transcriptome analyses revealed that NETs formation pathway promotes epithelial-mesenchymal transition (EMT). Furthermore, stimulation with NETs significantly up-regulated α-SMA, Twist, Snail protein expression, while decreasing the expression of E-cadherin protein in vitro. This indicates that NETosis promotes EMT in lung epithelial cells. Given drugs that are efficacious in degrading damaged NETs or inhibiting NETs production, we identified a few drug targets that were aberrantly expressed in both SLE and COVID-19. Among these targets, the JAK2 inhibitor Tofacitinib could effectively disrupted the process of NETs and reversed NET-induced EMT in lung epithelial cells. These findings support that the NETs/EMT axis, activated by SLE and COVID-19, contributes to the progression of pulmonary fibrosis. Our study also highlights that JAK2 as a potential target for the treatment of fibrosis in these diseases.

The prevalence of Dupuytren's disease in patients with diabetes mellitus

BACKGROUND

Dupuytren's disease (DD) is a fibroproliferative hand disorder associated with various medical conditions, including diabetes mellitus (DM). The reported prevalence of DM among DD patients varies widely, primarily due to small sample sizes in previous studies.

METHODS

This was a retrospective cohort study using data from the TriNetX Research Database. We analyzed the overall prevalence of DD between 2010 and 2020, comparing the DM, type 1 diabetes mellitus (T1DM), and type 2 diabetes mellitus (T2DM) cohorts. Within the DM group, patients were further categorized based on hemoglobin A1c (HbA1c) values and prescribed anti-diabetic agents (insulin or metformin). We compared the prevalence of DD diagnosis in each group using prevalence ratios and differences.

RESULTS

There is a higher prevalence of DD in patients with T2DM than in patients with T1DM (relative risk [RR]: 1.641; 95% confidence interval [CI]: [1.356, 1.986]). Among patients with diabetes, there is a higher prevalence of DD in those taking insulin compared to those taking metformin (RR: 0.801, 95% CI: [0.774, 0.83]). The prevalence of DD varies depending on HbA1c levels, with a prevalence of 0.463% in patients having levels within the diabetic range, while lower prevalences of 0.392% and 0.416% are found in patients with prediabetes or uncontrolled diabetes, respectively.

CONCLUSIONS

This study provides further insight into the relationship between DM and DD. These findings may be attributed to the increased accumulation of advanced glycosylated end products (AGEs) in patients with diabetes. Future research exploring the connection between AGE accumulation and DD development may enhance our understanding of the relationship between DD and DM.

An MRTF-A-ZEB1-IRF9 axis contributes to fibroblast-myofibroblast transition and renal fibrosis

Myofibroblasts, characterized by the expression of the matricellular protein periostin (Postn), mediate the profibrogenic response during tissue repair and remodeling. Previous studies have demonstrated that systemic deficiency in myocardin-related transcription factor A (MRTF-A) attenuates renal fibrosis in mice. In the present study, we investigated the myofibroblast-specific role of MRTF-A in renal fibrosis and the underlying mechanism. We report that myofibroblast-specific deletion of MRTF-A, achieved through crossbreeding Mrtfa-flox mice with Postn-Cre^ERT2 mice, led to amelioration of renal fibrosis. RNA-seq identified zinc finger E-Box binding homeobox 1 (Zeb1) as a downstream target of MRTF-A in renal fibroblasts. MRTF-A interacts with TEA domain transcription factor 1 (TEAD1) to bind to the Zeb1 promoter and activate Zeb1 transcription. Zeb1 knockdown retarded the fibroblast-myofibroblast transition (FMyT) in vitro and dampened renal fibrosis in mice. Transcriptomic assays showed that Zeb1 might contribute to FMyT by repressing the transcription of interferon regulatory factor 9 (IRF9). IRF9 knockdown overcame the effect of Zeb1 depletion and promoted FMyT, whereas IRF9 overexpression antagonized TGF-β-induced FMyT. In conclusion, our data unveil a novel MRTF-A-Zeb1-IRF9 axis that can potentially contribute to fibroblast-myofibroblast transition and renal fibrosis. Screening for small-molecule compounds that target this axis may yield therapeutic options for the mollification of renal fibrosis.

Dupuytren's disease: a localised and accessible human fibrotic disorder

We review the biology of Dupuytren's disease (DD), a common localised fibrotic disorder of the hand. The disease develops through a complex interplay of genetic and environmental factors, and epigenetic signalling. The early-stage disease nodules comprise a complex milieu of stromal and immune cells which interact to promote disease development. Recently, inhibition of tumour necrosis factor (TNF) locally resulted in softening and a decrease in nodule size, potentially controlling disease progression. Unlike fibrotic disorders of the visceral organs, the easy access to tissue in DD patients enables dissection of the cellular landscape and molecular signalling pathways. In addition, the study of DD may have wider benefits in enhancing our understanding of less-accessible fibrotic tissues.

IL-13/IL-4 signaling contributes to fibrotic progression of the myeloproliferative neoplasms

Myelofibrosis (MF) is a disease associated with high unmet medical needs because allogeneic stem cell transplantation is not an option for most patients, and JAK inhibitors are generally effective for only 2 to 3 years and do not delay disease progression. MF is characterized by dysplastic megakaryocytic hyperplasia and progression to fulminant disease, which is associated with progressively increasing marrow fibrosis. Despite evidence that the inflammatory milieu in MF contributes to disease progression, the specific factors that promote megakaryocyte growth are poorly understood. Here, we analyzed changes in the cytokine profiles of MF mouse models before and after the development of fibrosis, coupled with the analysis of bone marrow populations using single-cell RNA sequencing. We found high interleukin 13 (IL-13) levels in the bone marrow of MF mice. IL-13 promoted the growth of mutant megakaryocytes and induced surface expression of transforming growth factor β and collagen biosynthesis. Similarly, analysis of samples from patients with MF revealed elevated levels of IL-13 in the plasma and increased IL-13 receptor expression in marrow megakaryocytes. In vivo, IL-13 overexpression promoted disease progression, whereas reducing IL-13/IL-4 signaling reduced several features of the disease, including fibrosis. Finally, we observed an increase in the number of marrow T cells and mast cells, which are known sources of IL-13. Together, our data demonstrate that IL-13 is involved in disease progression in MF and that inhibition of the IL-13/IL-4 signaling pathway might serve as a novel therapeutic target to treat MF.

Revealing stromal and lymphoid sources of Col3a1-expression during inflammation using a novel reporter mouse

One of the earliest signs of dysregulation of the homeostatic process of fibrosis, associated with pathology in chronic conditions such as rheumatoid arthritis, is the overexpression of collagen type III (COL-3). Critically, there is still relatively little known regarding the identity of the cell types expressing the gene encoding COL-3 (Col3a1). Identifying and characterizing Col3a1-expressing cells during the development of fibrosis could reveal new targets for the diagnosis and treatment of fibrosis-related pathologies. As such, a reporter mouse expressing concomitantly Col3a1 and mKate-2, a fluorescent protein, was generated. Using models of footpad inflammation, we demonstrated its effectiveness as a tool to measure the expression of COL-3 during the repair process and provided an initial characterization of some of the stromal and immune cells responsible for Col3a1 expression.

Discovery of novel immunotherapeutic drug candidates for sciatic nerve injury using bioinformatic analysis and experimental verification

Inflammation following nerve injury and surgery often causes peripheral nerve adhesion (PNA) to the surrounding tissue. Numerous investigations independently examined the prevention or inhibition of PNA, however, an intervention targeting macrophages has not been fully elucidated. Basement membrane (BM) genes are known to modulate central nervous system (CNS) inflammation, however, their activities in the peripheral nervous system (PNS) remains undiscovered. In this report, we carried out weighted correlation network analysis (WCNA) to screen for principal sciatic nerve injury (SNI) module genes. Once an association between the module and BM genes was established, the protein–protein interaction (PPI) and immune infiltration analyses were employed to screen for relevant BM-related immune genes (Itgam, SDC1, Egflam, and CD44) in SNI. Subsequently, using the Drug SIGnatures (DSigDB) database and molecular docking, we demonstrated that Trichostatin A (TSA) interacted with key immune genes. TSA is known to enhance M2 macrophage expression and attenuate fibrosis. Nevertheless, the significance of the epigenetic modulation of macrophage phenotypes in dorsal root ganglion (DRG) is undetermined after SNI. In this article, we examined the TSA role in fibrogenesis and macrophage plasticity associated with DRG. We revealed that TSA enhanced M2 macrophage aggregation, inhibited fibroblast activation, and improved sciatic nerve regeneration (SNR) and sensory functional recovery (FR) after SNI. In addition, TSA suppressed M1 macrophages and enhanced M2 macrophage invasion within the DRG tissue. Furthermore, TSA dramatically reduced IL-1β and TNFα levels, while upregulating IL-10 level. In summary, this research revealed for the first time that TSA alleviates fibrosis in DRG by promoting an M1 to M2 macrophage transition, which, in turn, accelerates SNR.

Circulating inflammatory cytokines alter transcriptional activity within fibrotic tissue of Dupuytren's disease patients

Dupuytren's disease is a benign fibroproliferative disorder of the hand that results in disabling digital contractures that impair function and diminish the quality of life. The incidence of this disease has been correlated with chronic inflammatory states, but any direct association between inflammatory cytokines and Dupuytren's disease is not known. We hypothesized that advanced fibroproliferation is associated with increased levels of circulating inflammatory cytokines. Blood and fibrotic cord tissue were collected preoperatively from patients with severe contracture and control patients. Blood plasma concentrations of known inflammatory cytokines were evaluated using a multiplex immunoassay. Proteins from the cord tissue were analyzed by RNA sequencing and immunohistochemistry. Moreover, collagen-rich cords were analyzed using Fourier-transform infrared spectroscopy. The results indicate that patients exhibited significantly elevated circulating inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin (IL)-2, and IL-12p70, as compared with controls. Similarly, IL-4 and IL-13 were detected significantly more frequently in Dupuytren's disease as compared with control. RNA sequencing revealed 5311 differentially expressed genes and distinct clustering between diseased and control samples. In addition to increased expression of genes associated with fibroproliferation, we also observed upregulation of transcripts activated by inflammatory cytokines, including prolactin inducible protein and keratin intermediate filaments. IL-2, but not TNF-α, was detected in fibrotic cord tissue by immunohistochemistry. Finally, spectroscopic assays revealed a significant reduction of the collagen content and alterations of collagen cross-linking within the Dupuytren's disease tissues. In total, our results illustrate that patients with severe Dupuytren's disease exhibit substantially elevated circulating inflammatory cytokines that may drive fibroproliferation. Clinical Significance: The results from this study establish the basis for a specific cytokine profile that may be useful for diagnostic testing and therapeutic intervention in Dupuytren's disease.

Translational targeting of inflammation and fibrosis in frozen shoulder: Molecular dissection of the T cell/IL-17A axis

Frozen shoulder is a common fibroproliferative disease characterized by the insidious onset of pain and restricted range of shoulder movement with a significant socioeconomic impact. The pathophysiological mechanisms responsible for chronic inflammation and matrix remodeling in this prevalent fibrotic disorder remain unclear; however, increasing evidence implicates dysregulated immunobiology. IL-17A is a key cytokine associated with inflammation and tissue remodeling in numerous musculoskeletal diseases, and thus, we sought to determine the role of IL-17A in the immunopathogenesis of frozen shoulder. We demonstrate an immune cell landscape that switches from a predominantly macrophage population in nondiseased tissue to a T cell-rich environment in disease. Furthermore, we observed a subpopulation of IL-17A-producing T cells capable of inducing profibrotic and inflammatory responses in diseased fibroblasts through enhanced expression of the signaling receptor IL-17RA, rendering diseased cells more sensitive to IL-17A. We further established that the effects of IL-17A on diseased fibroblasts was TRAF-6/NF-κB dependent and could be inhibited by treatment with an IKKβ inhibitor or anti-IL-17A antibody. Accordingly, targeting of the IL-17A pathway may provide future therapeutic approaches to the management of this common, debilitating disease.

Inhibition of enhancer of zeste homolog 2 prevents corneal myofibroblast transformation in vitro

PURPOSE

Corneal fibroblast can be transformed into corneal myofibroblasts by TGF-β1. Enhancer of zeste homolog 2 (EZH2) upregulation has been observed in the occurrence of other fibrotic disorders. We investigated the role of EZH2 in the progression of corneal fibrosis and the antifibrotic effect of EZH2 inhibition in corneal fibroblasts (CFs).

METHODS

Primary CFs were isolated from corneal limbi and the CFs were treated with TGF-β1 to induce fibrosis. EPZ-6438 and EZH2 siRNA were used to inhibit EZH2 expression. Myofibroblast activation and extracellular matrix (ECM) protein synthesis was detected by quantitative real-time PCR, western blotting, and immunofluorescence staining assay. The functions of myofibroblast were evaluated by cell migration and collagen gel contraction assays. Molecular mechanisms involved in EZH2 inhibition were investigated by RNA sequencing.

RESULTS

TGF-β1 activated EZH2 expression in CFs. Treatment with EPZ-6438 (5 μM) and EZH2 siRNA considerably suppressed corneal myofibroblast activation and ECM protein synthesis in CFs induced by TGF-β1 when compared to the control group. EPZ-6438 (5 μM) suppressed cell migration and gel contraction in CFs. RNA sequencing results revealed that antifibrotic genes were activated after EZH2 inhibition to suppress corneal myofibroblast activation.

CONCLUSION

Inhibition of EZH2 suppresses corneal myofibroblast activation and ECM protein synthesis, and could serve as a novel therapeutic target for preventing corneal scarring.

Anaphylaxis: Focus on Transcription Factor Activity

Anaphylaxis is a severe allergic reaction, rapid in onset, and can lead to fatal consequences if not promptly treated. The incidence of anaphylaxis has risen at an alarming rate in past decades and continues to rise. Therefore, there is a general interest in understanding the molecular mechanism that leads to an exacerbated response. The main effector cells are mast cells, commonly triggered by stimuli that involve the IgE-dependent or IgE-independent pathway. These signaling pathways converge in the release of proinflammatory mediators, such as histamine, tryptases, prostaglandins, etc., in minutes. The action and cell targets of these proinflammatory mediators are linked to the pathophysiologic consequences observed in this severe allergic reaction. While many molecules are involved in cellular regulation, the expression and regulation of transcription factors involved in the synthesis of proinflammatory mediators and secretory granule homeostasis are of special interest, due to their ability to control gene expression and change phenotype, and they may be key in the severity of the entire reaction. In this review, we will describe our current understanding of the pathophysiology of human anaphylaxis, focusing on the transcription factors' contributions to this systemic hypersensitivity reaction. Host mutation in transcription factor expression, or deregulation of their activity in an anaphylaxis context, will be updated. So far, the risk of anaphylaxis is unpredictable thus, increasing our knowledge of the molecular mechanism that leads and regulates mast cell activity will enable us to improve our understanding of how anaphylaxis can be prevented or treated.

Minocycline alleviates peripheral nerve adhesion by promoting regulatory macrophage polarization via the TAK1 and its downstream pathway

AIMS

Inflammation plays a key role in peripheral nerve adhesion and often leads to severe pain and nerve dysfunction. Minocycline was reported to have potent anti-inflammatory effects and might be a promising drug to prevent or attenuate peripheral nerve adhesion. The present study aimed to clarify whether minocycline contributes to nerve adhesion protection and its underlying mechanism.

MATERIALS AND METHODS

Rats with sciatic nerve adhesion induced by glutaraldehyde glue (GG) were intraperitoneally injected with minocycline or saline every 12 h for 7 consecutive days. After that, the adhesion score, Ashcroft score, demyelination, macrophage polarization and inflammatory factors in peripheral nerve adhesion tissues or tissues in sham group were determined with histological staining, western blot and real time-PCR. Murine macrophage RAW264.7 cells were stimulated by LPS alone or together with minocycline at different concentrations and time duration to study the mechanism of minocycline in alleviating nerve adhesion.

KEY FINDINGS

We found that minocycline treatment reduced the adhesion score, Ashcroft score, the growth of scar tissue, demyelination, and macrophage recruitment. Moreover, minocycline significantly and dose-dependently promoted regulatory macrophage polarization but decreased pro-inflammatory macrophage polarization. Furthermore, mechanism studies showed that TAK1 and its downstream pathway p38/JNK/ERK1/2/p65 were inhibited by minocycline, which led to lower IL-1β and TNFα expression, but increased IL-10 expression.

SIGNIFICANCE

Altogether, these results suggest that minocycline is highly effective against peripheral nerve adhesion through anti-fibrosis, anti-inflammation, and myelination protection, making it a highly promising candidate for treating adhesion-related disorders.

Novel self-amplificatory loop between T cells and tenocytes as a driver of chronicity in tendon disease

OBJECTIVES

Increasing evidence suggests that inflammatory mechanisms play a key role in chronic tendon disease. After observing T cell signatures in human tendinopathy, we explored the interaction between T cells and tendon stromal cells or tenocytes to define their functional contribution to tissue remodelling and inflammation amplification and hence disease perpetuation.

METHODS

T cells were quantified and characterised in healthy and tendinopathic tissues by flow cytometry (FACS), imaging mass cytometry (IMC) and single cell RNA-seq. Tenocyte activation induced by conditioned media from primary damaged tendon or interleukin-1β was evaluated by qPCR. The role of tenocytes in regulating T cell migration was interrogated in a standard transwell membrane system. T cell activation (cell surface markers by FACS and cytokine release by ELISA) and changes in gene expression in tenocytes (qPCR) were assessed in cocultures of T cells and explanted tenocytes.

RESULTS

Significant quantitative differences were observed in healthy compared with tendinopathic tissues. IMC showed T cells in close proximity to tenocytes, suggesting tenocyte-T cell interactions. On activation, tenocytes upregulated inflammatory cytokines, chemokines and adhesion molecules implicated in T cell recruitment and activation. Conditioned media from activated tenocytes induced T cell migration and coculture of tenocytes with T cells resulted in reciprocal activation of T cells. In turn, these activated T cells upregulated production of inflammatory mediators in tenocytes, while increasing the pathogenic collagen 3/collagen 1 ratio.

CONCLUSIONS

Interaction between T cells and tenocytes induces the expression of inflammatory cytokines/chemokines in tenocytes, alters collagen composition favouring collagen 3 and self-amplifies T cell activation via an auto-regulatory feedback loop. Selectively targeting this adaptive/stromal interface may provide novel translational strategies in the management of human tendon disorders.