Bleomycin-induced Fibrosis Research Articles

Loss of interferon regulatory factor-1 prevents lung fibrosis by upregulation of pon1 expression

BackgroundInterferon regulatory factor-1 (IRF1) is a transcription factor that plays a significant role in various biological processes, including inflammatory injury, viral infection, cell death, and immune responses, and it has been extensively studied in the context of different lung diseases. However, the mechanism underlying its involvement in lung fibrosis remains largely unknown.MethodsWild type (WT) mice, IRF1 global-null mice (Irf1−/−) were subjected to a bleomycin-induced lung fibrosis model to enable examination of the role of IRF1 in lung fibrosis. Proteomic analysis of lung tissue from WT and Irf1−/− mice treated with saline or bleomycin was performed to explore the mechanism of IRF1 in regulating lung fibrosis.ResultsIn the bleomycin-induced fibrosis mouse model, increased expression of IRF1 was observed. Irf1 knockout mice displayed decreased lung fibrosis relative to WT mice following treatment with bleomycin. The protein expression of fibronectin, as assessed by the Western blot analysis of lung tissues, was downregulated in Irf1−/− mice. We observed a similar reduction in collagen content using hydroxyproline detection. Histologically, there was less collagen deposition in the lungs of Irf1−/− mice compared with WT mice. Proteomics data revealed that IRF1 may be involved in lung fibrosis via the regulation of ferroptosis. We determined that paraoxonase 1(PON1), a poorly characterized protein in lung fibrosis, was upregulated in Irf1−/− mice following exposure to bleomycin. In vitro experiments revealed that IRF1 could regulate the level of GSH and MDA through PON1. We also determined that PON1 levels were lower in the plasma of IPF patients compared with healthy controls.ConclusionOur data highlight the importance of IRF1 in the fibrotic process, and PON1 may be a potential mediator of IRF1 in the progression of lung fibrosis.

Cromolyn sodium and masitinib combination inhibits fibroblast-myofibroblast transition and exerts additive cell-protective and antioxidant effects on a bleomycin-induced invitro fibrosis model.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal fibrotic lung disease. While recent studies have suggested the potential efficacy of tyrosine kinase inhibitors in managing IPF, masitinib, a clinically used tyrosine kinase inhibitor, has not yet been investigated for its efficacy in fibrotic lung diseases. In a previous study on an invitro neurodegenerative model, we demonstrated the synergistic antitoxic and antioxidant effects of masitinib combined with cromolyn sodium, an FDA-approved mast cell stabilizer. This study aims to investigate the anti-fibrotic and antioxidant effects of the masitinib-cromolyn sodium combination in an invitro model of pulmonary fibrosis. Fibroblast cell cultures treated with bleomycin and/or hydrogen peroxide (H2O2) were subjected to masitinib and/or cromolyn sodium, followed by assessments of cell viability, morphological and apoptotic nuclear changes, triple-immunofluorescence labeling, and total oxidant/antioxidant capacities, besides ratio of Bax and Bcl-2 mRNA expressions as an indication of apoptosis. The combined treatment of masitinib and cromolyn sodium effectively prevented the fibroblast myofibroblast transition, a hallmark of fibrosis, and significantly reduced bleomycin / H2O2-induced apoptosis and oxidative stress. This study is the first to demonstrate the additive anti-fibrotic, cell-protective, and antioxidant effects of the masitinib-cromolyn sodium combination in an invitro fibrosis model, suggesting its potential as an innovative therapeutic approach for pulmonary fibrosis. Combination therapy may be more advantageous in that both drugs could be administered in lower doses, exerting less side effects, and at the same time providing diverse mechanisms of action simultaneously.

Spatial transcriptomic analysis deciphers adipocyte-to-fibroblast transformation in bleomycin-induced murine skin fibrosis.

Scleroderma is characterized by inflammation and fibrosis, predominantly occurring in the skin and extending to various parts of the body. The pathophysiology of scleroderma is multifaceted, with the current understanding including endothelial damage, inflammatory cell infiltration, and fibroblast activation in its progression. Nonetheless, the mechanism of cellular interactions and the precise spatial distribution of these cellular events within the fibrotic tissues remain elusive, highlighting a critical gap in our comprehensive understanding of scleroderma's pathogenesis. In this study, we administered bleomycin intradermally to the dorsal skin of four individual murine models. Subsequently, skin tissues were harvested at predetermined intervals for comprehensive spatial transcriptomic analysis to determine the spatial dynamics influencing scleroderma pathogenesis. To validate the possible results from bioinformatic analysis, further in vitro and in vivo experiments were conducted. Analysis of the spatial transcriptome revealed significant alterations in cell clusters during the progression of scleroderma. Gene Ontology analysis identified disruptions in lipid metabolism as the disease advanced. Pseudotime analysis provided evidence for a phenotypic transition from adipocytes to fibroblasts. In vitro studies demonstrated increased expression of Col1a1 and α-SMA as the disease progressed. These fibroblasts have been identified as key contributors to the increasing inflammation. Co-culturing TGF-β induced adipocytes with RAW264.7 cells resulted in overexpression of pro-inflammatory cytokines in the RAW264.7 cells. Both in vitro and in vivo experiments confirmed adipocyte loss and fibroblast formation, with transformed fibroblasts showing pronounced pro-inflammatory characteristics, highlighting their crucial role in the disease mechanism. Our study showed the spatial distribution and dynamic alterations of various cell types during scleroderma progression. Crucially, we identified the transformation of adipocytes into fibroblasts as a key factor promoting disease advancement. These emergent fibroblasts intensify inflammation, indicating that research on these cell clusters could reveal key scleroderma mechanisms and guide future therapies.

Targeting CD13/aminopeptidase N as a novel therapeutic approach for scleroderma fibrosis.

Systemic sclerosis (SSc) is an autoimmune multisystem disease with poorly understood pathogenesis and ineffective treatment options. Soluble CD13 (sCD13), generated by cleavage of cell surface CD13 via matrix metalloproteinase 14 (MMP14), signals through the bradykinin receptor B1 (B1R) to elicit pro-inflammatory, pro-arthritic, and pro-angiogenic responses. In this study we explored the anti-fibrotic potential of targeting the sCD13-B1R axis in SSc. The expression of CD13, B1R and MMP14 was examined in SSc skin and explanted dermal fibroblasts. The efficacy of B1R antagonists in the inhibition on fibrosis was determined in vitro and in vivo. Expression of the genes for CD13, B1R and MMP14 was elevated in skin biopsies from patients with diffuse cutaneous (dc)SSc. Notably, single cell analysis of SSc skin biopsies revealed the highest BDKRB1 expression in COL8A1-positive myofibroblasts, a population exclusively seen in SSc. TGF-β induced the expression of BDKRB1 and production of sCD13 by dcSSc skin fibroblasts. Treatment of dcSSc fibroblasts with sCD13 promoted fibrotic gene expression, signaling, cell proliferation, migration, and gel contraction. The profibrotic sCD13 or TGFβ responses were prevented by a B1R antagonist. Mice lacking Cd13 or Bdkrb1 were resistant to bleomycin-induced skin fibrosis and inflammation. Pharmacological B1R inhibition had a comparable antifibrotic effect. These results are the first to demonstrate a key role for sCD13 in SSc skin fibrosis, and suggest that targeting the sCD13-B1R signaling axis is a promising novel therapeutic approach for SSc.

Unraveling the role of MiR-181 in skin fibrosis pathogenesis by targeting NUDT21.

Systemic sclerosis (SSc) is a life-threatening autoimmune disease characterized by widespread fibrosis in the skin and several internal organs. Nudix Hydrolase 21 (NUDT2 or CFIm25) downregulation in fibroblasts is known to play detrimental roles in both skin and lung fibrosis. This study aims to investigate the upstream mechanisms that lead to NUDT21 repression in skin fibrosis. We identified transforming growth factor β (TGFβ1) as the primary cytokine that downregulated NUDT21 in normal skin fibroblasts. In the bleomycin-induced dermal fibrosis model, consistent with the peak activation of TGFβ1 at the late fibrotic stage, NUDT21 was downregulated at this stage, and delayed NUDT21 knockdown during this fibrotic phase led to enhanced fibrotic response to bleomycin. Further investigation suggested TGFβ downregulated NUDT21 through microRNA (miRNA) 181a and 181b induction. Both miR-181a and miR-181b were elevated in bleomycin-induced skin fibrosis in mice and primary fibroblasts isolated from SSc patients, and they directly targeted NUDT21 and led to its downregulation in skin fibroblasts. Functional studies demonstrated that miR-181a and miR-181b inhibitors attenuated bleomycin-induced skin fibrosis in mice in association with decreased NUDT21 expression, while miR-181a and miR-181b mimics promoted bleomycin-induced fibrosis. Overall, these findings suggest a novel role for miR-181a/b in SSc pathogenesis by repressing NUDT21 expression.

Bleomycin-Induced Fibrosis and the Effectiveness of Centella Asiatica as a Treatment.

Plant treatment has been used for thousands of years and has been proven to treat acute and chronic diseases. The function of the traditional plant Centella asiatica is as an antimicrobial agent, anticancer, antioxidant, and therapeutic gene in healing wounds and inflammation. Lung fibrosis caused by bleomycin can develop into chronic lung disease, which ends in tissue death if not treated immediately. The purpose of this study is to predict and explain the impact of Centella asiatica extract on model rats exposed to bleomycin in their lungs as a treatment or anti-fibrinolysis. This research is an analytical study with a randomized in-vivo experimental design divided into 3 groups of 5 male Wistar rats aged 10 weeks. Negative control group (K) with intratracheal induction of bleomycin alone. The positive group was given intratracheal bleomycin 4 mg/kg/BB on days 0 and 21 and added Centella asiatica induction at 400 mg (P1) on days 15 to 49. The other positive group was given intratracheal bleomycin 4 mg/kg/BB on days 0 and 21 and added Centella asiatica induction at 800 mg (P2) on days 15 to 49. Data were collected according to findings of lung histology analysis of rat samples. In the interalveolar septum group, there was a difference in Masson's Trichrome staining results in groups K and P1 with p<0.05 (p=0.036). However, there was no difference in histopathological staining results in groups K and P2 (p>0.05). The induction of bleomycin 4 mg/kg/BB was proven to cause fibrosis in the lungs of rats, and Centella asiatica extract was used as a treatment. Therefore, further research regarding antifibrotic drugs is hoped to reduce fibrotic areas significantly.

Single-cell RNA sequencing identifies inherent abnormalities of adipose-derived stem cells from nonlesional sites of patients with localized scleroderma

BackgroundLocalized scleroderma (LoS) is an autoimmune disorder that primarily affects the skin, and is often treated with autologous fat grafting (AFG). Nevertheless, the retention rate of AFG in patients with LoS is typically low. We hypothesize that the low retention rate may be partially attributed to the inherent abnormalities of adipose-derived stem cells (ASCs) from nonlesional sites of patients with LoS.MethodsWe performed a comparative analysis of the single-cell transcriptome of the SVF from nonlesional sites of patients with LoS and healthy donors, including cellular compositional analysis, differential expression analysis, and high-dimensional weighted gene coexpression network analysis. Experimental validation with fluorescence-activated cell sorting and bleomycin-induced skin fibrosis mice models were conducted.ResultsWe found a significant reduction in the relative proportion of CD55high interstitial progenitors in ASCs under the condition of LoS. Differential expression analysis revealed inherent abnormalities of ASCs from patients with LoS, including enhanced fibrogenesis, reduced anti-inflammatory properties, and increased oxidative stress. Compared with CD55low ASCs, CD55high ASCs expressed significantly higher levels of secreted protein genes that had functions related to anti-inflammation and tissue regeneration (such as CD55, MFAP5, and METRNL). Meanwhile, CD55high ASCs expressed significantly lower levels of secreted protein genes that promote inflammation, such as chemokine and complement protein genes. Furthermore, we provided in vivo experimental evidence that CD55high ASCs had superior treatment efficacy compared with CD55low ASCs in bleomycin-induced skin fibrosis mice models.ConclusionsWe found that the low retention rate of AFG may be partially ascribed to the reduced pool of interstitial progenitor cells (CD55high) present within the ASC population in patients with LoS. We demonstrated the potential for improving the efficacy of AFG in the treatment of LoS by restoring the pool of interstitial progenitors within ASCs. Our study has significant implications for the field of translational regenerative medicine.

Combined inhibition of IL-1, IL-33 and IL-36 signalling by targeting IL1RAP ameliorates skin and lung fibrosis in preclinical models of systemic sclerosis

BackgroundThe interleukin (IL)-1 receptor accessory protein (IL1RAP) is an essential coreceptor required for signalling through the IL-1, IL-33 and IL-36 receptors. Here, we investigate the antifibrotic potential of the combined...

Dihydroquercetin-Loaded Liposomes Change Fibrous Tissue Distribution in the Bleomycin-Induced Fibrosis Model.

The effects of the antioxidant dihydroquercetin (DHQ) were studied in a model of pulmonary fibrosis. DHQ penetration into the lesion was facilitated by encapsulation into liposomes. Pulmonary fibrosis was modeled in rats by intratracheal injection of bleomycin. For the first 7 days, the rats in the treatment group received a liposomal emulsion with DHQ, while in the comparator group rats received saline. In the control group, intact rats did not receive any exposure. Thirty days after the initiation, lung function and the pathological lesion volume were assessed by 7T 1H MRI and the lungs were taken for histologic examination. The proportion of fibrous tissue was counted by Masson's trichrome staining. Both experimental groups were characterized by a significant functional pulmonary deficiency, with low mortality and a small lesion area. In the rats treated with DHQ, the distribution of fibrous tissue was significantly altered. Significantly more fibrous tissue was found in the center of the lesion, while significantly less was in the interstitial space of alveoli. Lung density at the same time was lower in the treated lungs. Dihydroquercetin encapsulated in liposomes affects the mechanisms of bleomycin-induced pulmonary fibrosis progression in rats. While accelerated fibrosis of the lesion can restrict inflammatory processes, delayed fibrosis of the interstitium can further improve the functional state of the lungs.

Resveratrol ameliorates pathological fibrosis of the myodural bridge by regulating the SIRT3/TGF-β1/Smad pathway

PurposePathological fibrosis of the myodural bridge (MDB) affects cerebrospinal fluid circulation. However, no optimal drug treatments are available. We aimed to explore the antifibrotic effect of resveratrol on bleomycin-induced pathological fibrosis of the MDB and its underlying mechanisms. MethodsGenes common to the potential targets of resveratrol were determined using network pharmacology, genes related to muscle and tendon fibrosis were acquired from the GeneCards database, and genes related to MDB development were determined using Venny. These genes were considered potential resveratrol treatment targets in bleomycin-induced pathological fibrosis of the MDB and were annotated using bioinformatics methods. We validated the intersected genes using quantitative real-time polymerase chain reaction (qRT-PCR) and performed molecular docking analysis to calculate the binding activity between the target gene and resveratrol. Hematoxylin and eosin and Masson staining were used to detect the morphological changes in bleomycin-induced fibrosis of the MDB following resveratrol treatment. We used qRT-PCR and immunohistochemistry to evaluate the expression of the sirtuin 3 (SIRT3)/transforming growth factor-β1 (TGF-β1)/Smad pathway and the profibrotic markers α-smooth muscle actin (α-SMA) and Collagen Ⅰ. ResultsThrough network pharmacology and bioinformatics analyses, we identified four core intersected genes, and SIRT3 expression was validated using qRT-PCR. Molecular docking analysis revealed that resveratrol had good binding affinity for SIRT3. Resveratrol ameliorated morphological abnormalities in bleomycin-induced pathological fibrosis of the MDB by inhibiting fibroblast activation and excessive collagen fiber deposition. Resveratrol exerted its antifibrotic effect by regulating the SIRT3/TGF-β1/Smad pathway. ConclusionResveratrol has an antifibrotic effect in bleomycin-induced pathological fibrosis of the MDB in vivo and may be considered a novel therapeutic strategy.

Targeting CEBPA to restore cellular identity and tissue homeostasis in pulmonary fibrosis.

Fibrosis in the lung is thought to be driven by epithelial cell dysfunction and aberrant cell-cell interactions. Unveiling the molecular mechanisms of cellular plasticity and cell-cell interactions is imperative to elucidating lung regenerative capacity and aberrant repair in pulmonary fibrosis. By mining publicly available RNA-Seq data sets, we identified loss of CCAAT enhancer-binding protein alpha (CEBPA) as a candidate contributor to idiopathic pulmonary fibrosis (IPF). We used conditional KO mice, scRNA-Seq, lung organoids, small-molecule inhibition, and potentially novel gene manipulation methods to investigate the role of CEBPA in lung fibrosis and repair. Long-term (6 months or more) of Cebpa loss in AT2 cells caused spontaneous fibrosis and increased susceptibility to bleomycin-induced fibrosis. Cebpa knockout (KO) in these mice significantly decreased AT2 cell numbers in the lung and reduced expression of surfactant homeostasis genes, while increasing inflammatory cell recruitment as well as upregulating S100a8/a9 in AT2 cells. In vivo treatment with an S100A8/A9 inhibitor alleviated experimental lung fibrosis. Restoring CEBPA expression in lung organoids ex vivo and during experimental lung fibrosis in vivo rescued CEBPA deficiency-mediated phenotypes. Our study establishes a direct mechanistic link between CEBPA repression, impaired AT2 cell identity, disrupted tissue homeostasis, and lung fibrosis.

Let‑7f‑5p Regulated by Hsa_circ_0000437 Ameliorates Bleomycin-Induced Skin Fibrosis.

The current treatment of skin fibrosis is limited in its effectiveness due to a lack of understanding of the underlying mechanisms. Previous research has shown a connection between microRNAs (miRNAs) and the development of skin fibrosis. Therefore, investigating miRNA for the treatment of skin fibrotic diseases is highly important and merits further exploration. In this study, we have discovered that let-7f-5p could suppress the proliferation, migration, and expression of collagen type I alpha 1 (COL1A1) in human dermal fibroblasts (HDFs). It was further determined that let-7f-5p could target thrombospondin-1 (THBS1), thereby inhibiting the TGF-β2/Smad3 signaling pathway and exerting its biological effects. Additionally, let-7f-5p is regulated by Hsa_circ_0000437, which acts as a sponge molecule for let-7f-5p and consequently regulates the biological function of HDFs. Furthermore, our findings indicate that in vivo overexpression of let-7f-5p leads to a reduction in dermal thickness and COL1A1 expression, effectively inhibiting the progression of bleomycin (BLM)-induced skin fibrosis in mice. Hence, our research enhances the comprehension of the Hsa_circ_0000437/let-7f-5p/THBS1/TGF-β2/Smad3 regulatory network, highlighting the potential of let-7f-5p as a therapeutic approach for the treatment of skin fibrosis.

Mitochondrial DNA mutations attenuate Bleomycin-induced dermal fibrosis by inhibiting differentiation into myofibroblasts

Post-mitotic, non-proliferative dermal fibroblasts have crucial functions in maintenance and restoration of tissue homeostasis. They are involved in essential processes such as wound healing, pigmentation and hair growth, but also tumor development and aging-associated diseases. These processes are energetically highly demanding and error prone when mitochondrial damage occurs. However, mitochondrial function in fibroblasts and the influence of mitochondrial dysfunction on fibroblast-specific demands are still unclear. To address these questions, we created a mouse model in which accelerated cell-specific mitochondrial DNA (mtDNA) damage accumulates. We crossed mice carrying a dominant-negative mutant of the mitochondrial replicative helicase Twinkle (RosaSTOP system) with mice that express fibroblast-specific Cre Recombinase (Collagen1A2 CreERT) which can be activated by Tamoxifen (TwinkleFIBRO). Thus, we are able to induce mtDNA deletions and duplications in specific cells, a process which resembles the physiological aging process in humans, where this damage accumulates in all tissues. Upon proliferation in vitro, Tamoxifen induced Twinkle fibroblasts deplete most of their mitochondrial DNA which, although not disturbing the stoichiometry of the respiratory chain complexes, leads to reduced ROS production and mitochondrial membrane potential as well as an anti-inflammatory and anti-fibrotic profile of the cells. In Sodium Azide treated wildtype fibroblasts, without a functioning respiratory chain, we observe the opposite, a rather pro-inflammatory and pro-fibrotic signature. Upon accumulation of mitochondrial DNA mutations in vivo the TwinkleFIBRO mice are protected from fibrosis development induced by intradermal Bleomycin injections. This is due to dampened differentiation of the dermal fibroblasts into α−smooth-muscle-actin positive myofibroblasts in TwinkleFIBRO mice. We thus provide evidence for striking differences of the impact that mtDNA mutations have in contrast to blunted mitochondrial function in dermal fibroblasts and skin homeostasis. These data contribute to improved understanding of mitochondrial function and dysfunction in skin and provide mechanistic insight into potential targets to treat skin fibrosis in the future.

Exploring the preventive effects of Jie Geng Tang on pulmonary fibrosis induced in vitro and in vivo: a network pharmacology approach.

Pulmonary fibrosis is a debilitating lung disease marked by excessive fibrotic tissue accumulation, which significantly impairs respiratory function. Given the limitations of current therapies, there is an increasing interest in exploring traditional herbal formulations like Jie Geng Tang (JGT) for treatment. This study examines the potential of JGT and its bioactive component, quercetin, in reversing bleomycin (BLM)-induced pulmonary fibrosis in mice. We employed a BLM-induced MLE-12 cell damage model for in vitro studies and a bleomycin-induced fibrosis model in C57BL/6 mice for in vivo experiments. In vitro assessments showed that JGT significantly enhanced cell viability and reduced apoptosis in MLE-12 cells treated with BLM. These findings underscore JGT's potential for cytoprotection against fibrotic agents. In vivo, JGT was effective in modulating the expression of E-cadherin and vimentin, key markers of the epithelial-mesenchymal transition (EMT) pathway, indicating its role in mitigating EMT-associated fibrotic changes in lung tissue. Quercetin, identified through network pharmacology analysis as a potential key bioactive component of JGT, was highlighted for its role in the regulatory mechanisms underlying fibrosis progression, particularly through the modulation of the IL-17 pathway and Il6 expression. By targeting inflammatory pathways and key processes like EMT, JGT and quercetin offer a potent alternative to conventional therapies, meriting further clinical exploration to harness their full therapeutic potential in fibrotic diseases.

Integrating metabolomics and network pharmacology analysis to explore mechanism of Pueraria lobata against pulmonary fibrosis: Involvement of arginine metabolism pathway

Ethnopharmacological relevancePueraria lobata (Willd.) Ohwi is a typical medicinal and edible plant with a long application history in China and Southeast Asia. As a widely used traditional medicine, P. lobata exhibits the properties of anti-inflammatory, antipyretic, antioxidant, relieving cough and asthma. Particularly, the increasing evidence indicates that the P. lobata has the therapeutic effect on fibrotic-related diseases in terms of metabolic regulation. However, the mechanisms of P. lobata on pulmonary fibrosis (PF) has not been thoroughly explored. Aim of the studyThis study aimed to explore the effect of arginine metabolites of P. lobata against PF model by integrating metabolomics and network pharmacology analysis. It might provide a new idea for the target finding of P. lobata anti-pulmonary fibrosis. Materials and methodsIn this study, the Sprague Dawley (SD) rats were randomly divided into five experimental groups: saline-treated control group, bleomycin-induced fibrosis group, prednisolone acetate group, P. lobata 3.2 g/kg group and P. lobata 6.4 g/kg group. The therapeutic effect of P. lobata on bleomycin-induced PF in rats was evaluated by clinical symptoms such as lung function, body weight, hematoxylin eosin staining (HE), Masson staining and hydroxyproline assay. Next, the plasma metabolomics analysis was carried out by LC-MS to explore the pathological differences between the group of control, PF and P. lobata-treated rats. Then, the network pharmacology study coupled with experimental validation was conducted to analysis the results of metabolic research. We constructed the “component-target-disease” network of P. lobata in the treatment of PF. In addition, the molecular docking method was used to verify the interaction between potential active ingredients and core targets of P. lobata. Finally, we tested NOS2 and L-OT in arginine-related metabolic pathway in plasma of the rats by enzyme-linked immunosorbent assay (ELISA). Real-time PCR was performed to observe the level of TNF-α mRNA and MMP9 mRNA. And we tested the expression of TNF-α and MMP9 by Western blot analysis. ResultsOur findings revealed that P. lobata improved lung function and ameliorated the pathological symptoms, such as pathological damage, collagen deposition, and body weight loss in PF rats. Otherwise, the plasma metabolomics were employed to screen the differential metabolites of amino acids, lipids, flavonoids, arachidonic acid metabolites, glycoside, etc. Finally, we found that the arginine metabolism signaling mainly involved in the regulating of P. lobata on the treatment of PF rats. Furtherly, the network pharmacology predicted that the arginine metabolism pathway was contained in the top 20 pathways. Next, we integrated metabolomics and network pharmacology that identified NOS2, MMP9 and TNF-α as the P. lobata regulated hub genes by molecular docking. Importantly, it indicated a strong affinity between the puerarin and the NOS2. P. lobata attenuated TNF-α, MMP-9 and NOS2 levels, suppressed TNF-α and MMP-9 protein expression, and decreased L-OT and NOS2 content in PF rats. These results indicated that the effects of P. lobata may ameliorated PF via the arginine metabolism pathway in rats. Therefore, P. lobata may be a potential therapeutic agent to ameliorated PF. ConclusionIn this work, we used metabolomics and network pharmacology to explore the mechanisms of P. lobata in the treatment of PF. Finally, we confirmed that P. lobata alleviated BLM-induced PF in rats by regulating arginine metabolism pathway based on reducing the L-OT and NOS2-related signal molecular. The search for the biomarkers finding of arginine metabolism pathway revealed a new strategy for P. lobata in the treatment of PF.

P17 Dissection of the molecular and cellular heterogeneity of dermal fibroblasts in skin fibrosis

Abstract Introduction and aims Skin fibrosis, a common fibrotic condition that currently has no specific treatments or cures, is caused by persistent activation of skin fibroblasts after tissue injury that Results in excessive scarring, can cause severe disability and seriously affect morbidity. This study aims to uncover the specific fibroblast subsets and molecular pathways that are integral to this sustained fibroblast activation using a bleomycin-induced skin fibrosis mouse model that accurately recapitulates the human disease. Methods We have successfully shown that 2 weeks (early) and 4 weeks (advanced) of bleomycin injections Results in an increasing severity of skin fibrosis characteristics. Following this treatment, we performed single-cell RNA sequencing (scRNA-Seq) using control, early and advanced fibrotic tissue and identified fibroblast subclusters and specific gene signatures that are altered across the time course and may play a role in the fibrotic phenotype we observe. The use of advanced scRNA-Seq analysis techniques such as SCENIC and regulon analysis has allowed us to further characterize the changes in fibroblast states during fibrosis. Results Our scRNA-Seq data show a loss of fibroblast heterogeneity alongside the emergence of two main subclusters with distinct gene signatures in the advanced fibrotic state. While proliferation is minimal, RNA velocity analysis indicates that the increase in cell count is due to the convergence of neighbouring fibroblast subclusters. The pronounced profibrotic gene expression point to its key role in driving skin fibrosis and we are now exploring the therapeutic potential of chemically or genetically targeting this subcluster. Conclusions Our novel skin fibrosis time course scRNA-Seq dataset allows us to compare the cellular and molecular changes in early and advanced fibrotic lesions in order to identify the key fibroblast subpopulations, molecular regulators and connective tissue alterations promoting fibrotic tissue repair. Our findings will support the development of new fibroblast-targeted fibrosis therapies in skin and potentially in other organs.

EphB2 Receptor Promotes Dermal Fibrosis in Systemic Sclerosis.

Erythropoietin-producing hepatocellular (Eph)/Ephrin cell-cell signaling is emerging as a key player in tissue fibrogenesis. The aim of this study was to test the hypothesis that the receptor tyrosine kinase EphB2 mediates dermal fibrosis in systemic sclerosis (SSc). We assessed normal and SSc human skin biopsies for EphB2 expression. The in vivo role of EphB2 in skin fibrosis was investigated by subjecting EphB2-knockout mice to both bleomycin-induced and tight skin (Tsk1/+) genetic mouse models of skin fibrosis. EphB2 kinase-dead and overactive point mutant mice were used to evaluate the role of EphB2 forward signaling in bleomycin-induced dermal fibrosis. In vitro studies were performed on dermal fibroblasts from patients with SSc and healthy controls, which was followed by in vivo analysis of fibroblast-specific Ephb2-deficient mice. Expression of EphB2 is up-regulated in SSc skin tissue and explanted SSc dermal fibroblasts compared with healthy controls. EphB2 expression is elevated in two animal models of dermal fibrosis. In mice, EphB2 drives dermal fibrosis in both the bleomycin and the Tsk1/+ models of skin fibrosis. EphB2 forward signaling is a critical mediator of dermal fibrosis. Transforming growth factor-β (TGF-β) cytokines up-regulate EphB2 in dermal fibroblasts via noncanonical TGF-β/mother against decapentaplegic signaling, and silencing EPHB2 in human dermal fibroblasts is sufficient to dampen TGF-β-induced fibroblast-to-myofibroblast differentiation. Moreover, mice with fibroblast-specific deletion of EphB2 showed impaired fibroblast-to-myofibroblast differentiation and reduced skin fibrosis upon bleomycin challenge. Our data implicate TGF-β regulation of EphB2 overexpression and kinase-mediated forward signaling in the development of dermal fibrosis in SSc. EphB2 thus represents a potential new therapeutic target for SSc.

Cadherin-11 targeted cell-specific liposomes enabled skin fibrosis treatment by inducing apoptosis

Continuous and aberrant activation of myofibroblasts is the hallmark of pathological fibrosis (e.g., abnormal wound healing). The deposition of excessive extracellular matrix (ECM) components alters or increases the stiffness of tissue and primarily accounts for multiple organ dysfunctions. Among various proteins, Cadherin-11 (CDH11) has been reported to be overexpressed on myofibroblasts in fibrotic tissues. Anti-apoptotic proteins such as (B cell lymphoma-2) (BCL-2) are also upregulated on myofibroblasts. Therefore, we hypothesize that CDH11 could be a targeted domain for cell-specific drug delivery and targeted inhibition of BCL-2 to ameliorate the development of fibrosis in the skin. To prove our hypothesis, we have developed liposomes (LPS) conjugated with CDH11 neutralizing antibody (antiCDH11) to target cell surface CDH11 and loaded these LPS with a BCL-2 inhibitor, Navitoclax (NAVI), to induce apoptosis of CDH11 expressing fibroblasts. The developed LPS were evaluated for physicochemical characterization, stability, in vitro therapeutic efficacy using dermal fibroblasts, and in vivo therapeutic efficacy in bleomycin-induced skin fibrosis model in mice. The findings from in vitro and in vivo studies confirmed that selectivity of LPS was improved towards CDH11 expressing myofibroblasts, thereby improving therapeutic efficacy with no indication of adverse effects. Hence, this novel research work represents a versatile LPS strategy that exhibits promising potential for treating skin fibrosis.

F127-SE-tLAP thermosensitive hydrogel alleviates bleomycin-induced skin fibrosis via TGF-β/Smad pathway

BackgroundSkin fibrosis affects the normal function of the skin. TGF-β1 is a key cytokine that affects organ fibrosis. The latency-associated peptide (LAP) is essential for TGF-β1 activation. We previously constructed and prepared truncated LAP (tLAP), and confirmed that tLAP inhibited liver fibrosis by affecting TGF-β1. SPACE peptide has both transdermal and transmembrane functions. SPACE promotes the delivery of macromolecules through the stratum corneum into the dermis. This study aimed to alleviate skin fibrosis through the delivery of tLAP by SPACE.MethodsThe SPACE-tLAP (SE-tLAP) recombinant plasmid was constructed. SE-tLAP was purified by nickel affinity chromatography. The effects of SE-tLAP on the proliferation, migration, and expression of fibrosis-related and inflammatory factors were evaluated in TGF-β1-induced NIH-3T3 cells. F127-SE-tLAP hydrogel was constructed by using F127 as a carrier to load SE-tLAP polypeptide. The degradation, drug release, and biocompatibility of F127-SE-tLAP were evaluated. Bleomycin was used to induce skin fibrosis in mice. HE, Masson, and immunohistochemistry were used to observe the skin histological characteristics.ResultsSE-tLAP inhibited the proliferation, migration, and expression of fibrosis-related and inflammatory factors in NIH-3T3 cells. F127-SE-tLAP significantly reduced ECM production, collagen deposition, and fibrotic pathological changes, thereby alleviating skin fibrosis.ConclusionF127-SE-tLAP could increase the transdermal delivery of LAP, reduce the production and deposition of ECM, inhibit the formation of dermal collagen fibers, and alleviate the progression of skin fibrosis. It may provide a new idea for the therapy of skin fibrosis.

Ketotifen directly modifies the fibrotic response of human skin fibroblasts

Fibrosis is a destructive, end-stage disease process. In the skin, it is associated with systemic sclerosis and scarring with considerable health burden. Ketotifen is a clinical antihistamine and mast cell stabilizer. Studies have demonstrated mast cell-dependent anti-fibrotic effects of ketotifen but direct effects on fibroblasts have not been determined. Human dermal fibroblasts were treated with pro-fibrotic transforming growth factor-β1 (TGFβ) followed by ketotifen or control treatments to determine direct effects on fibrotic fibroblasts. Ketotifen impaired TGFβ-induced α-smooth muscle actin gene and protein responses and decreased cytoskeletal- and contractility-associated gene responses associated with fibrosis. Ketotifen reduced Yes-associated protein phosphorylation, transcriptional coactivator with PDZ binding motif transcript and protein levels, and phosphorylation of protein kinase B. In a fibroblast-populated collagen gel contraction assay, ketotifen reduced the contractile activity of TGFβ-activated fibroblasts. In a murine model of bleomycin-induced skin fibrosis, collagen density and dermal thickness were significantly decreased in ketotifen-treated mice supporting in vitro findings. These results support a novel, direct anti-fibrotic activity of ketotifen, reducing pro-fibrotic phenotypic changes in fibroblasts and reducing collagen fibres in fibrotic mouse skin. Together, these findings suggest novel therapeutic potential and a novel mechanism of action for ketotifen in the context of fibrosis.