Excessive Extracellular Matrix Production Research Articles

Aging, ROS, and cellular senescence: a trilogy in the progression of liver fibrosis.

Ageing is an inevitable and multifaceted biological process that impacts a wide range of cellular and molecular mechanisms, leading to the development of various diseases, such as liver fibrosis. Liver fibrosis progresses to cirrhosis, which is an advanced form due to high amounts of extracellular matrix and restoration of normal liver structure with failure to repair damaged tissue and cells, marking the end of liver function and total liver failure, ultimately death. The most important factors are reactive oxygen species (ROS) and cellular senescence. Oxidative stress is defined as an impairment by ROS, which are by-products of the mitochondrial electron transport chain and other key molecular pathways that induce cell damage and can activate cellular senescence pathways. Cellular senescence is characterized by pro-inflammatory cytokines, growth factors, and proteases secreted by senescent cells, collectively known as the senescence-associated secretory phenotype (SASP). The presence of senescent cells, which disrupt tissue architecture and function and increase senescent cell production in liver tissues, contributes to fibrogenesis. Hepatic stellate cells (HSCs) are activated in response to chronic liver injury, oxidative stress, and senescence signals that drive excessive production and deposition of extracellular matrix. This review article aims to provide a comprehensive overview of the pathogenic role of ROS and cellular senescence in the aging liver and their contribution to fibrosis.

KIAA1429 Promotes Keloid Formation Through the TGF-Β1/Smad Pathway.

Keloid formation is characterized by excessive production of extracellular matrix, leading to dysregulated fibroproliferative collagen response. N6- methyl-adenosine (m6A) modification plays an essential role in this process. Our objective in this study was to explore the mechanism of m6A methyltransferase KIAA1429 in keloid formation. We examined the impact of m6A methyltransferase KIAA1429 on keloid formation using qRT-PCR, Western blot, immunofluorescence, Transwell migration assay, and MeRIP-qPCR. KIAA1429 was downregulated in keloid tissue. Overexpression of KIAA1429 suppressed fibroblast migration and reduced COL1A1 and α-SMA levels. Conversely, the knockdown of KIAA1429 promoted fibroblast migration and COL1A1 and α-SMA levels. Additionally, overexpression of KIAA1429 inhibited the TGF-β1/Smad pathway. Mechanistic experiments suggested that KIAA1429 regulated TGF-β1 m6A modification, maintained TGF-β1 mRNA stability, and participated in the regulation of keloid formation. Furthermore, TGF-β1 could reverse the effects of KIAA1429 overexpression on fibroblast migration and collagen deposition. Taken together, our study suggested that KIAA1429 promoted keloid formation through the TGF-β1/Smad pathway, providing new insights for the treatment of keloid.

Novel therapeutic strategy for intractable keloids: Suppression of intracellular mechanotransduction and actin polymerisation via Rho-kinase pathway inhibition.

Keloid is a dermal fibrotic disorder characterised by excessive extracellular matrix production by fibroblasts. Despite the significance of mechanostimulation in fibrotic diseases, its association with keloid pathophysiology or treatment remains unexplored. We investigated the role of mechanical force in keloid formation and elucidated the significance of Rho-associated coiled-coil-containing kinase 1 (ROCK1) as a mechanoresponsive target for keloid treatment. Patient-derived keloid fibroblasts (KFs) were subjected to cyclic stretching ranging from 0 to 20% elongation using a cell-stretching system. We observed the inhibitory effects of the ROCK1 inhibitor Y27632 on KFs and keloid formation. Validation was performed using keloid xenograft severe combined immune-deficient (SCID) mouse model. ROCK1 was overexpressed in KFs isolated from patients. Cyclic stretching induced fibroblast proliferation and actin polymerisation by activating Rho/ROCK1 signalling. Treatment with Y27632 downregulated fibrotic markers, reduced the migration capacity of KFs, and induced extensive actin cytoskeleton remodelling. In keloid xenograft SCID mouse model, Y27632 effectively suppressed keloid formation, mitigating inflammation and fibrosis. The ROCK1 inhibitor Y27632 is a promising molecule for keloid treatment, exerting its effects through actin cytoskeleton remodelling and nuclear inhibition of fibrotic markers in keloid pathogenesis.

Anti-fibrotic Potential of WJ-MSC Exosomes in Liver Fibrosis: Mechanistic Insights and Dose-Response Efficacy

Background: Hepatic fibrosis is a biological response characterized by the accumulation of extracellular matrix (ECM) during the wound healing process. Hepatic stellate cells (HSCs) play a pivotal role in fibrogenesis, transitioning from quiescent to myofibroblast cell types and leading to excessive ECM production. Platelet-derived growth factor (PDGF), a potent mitogen, is produced by activated HSCs, stimulating cell proliferation and migration. Objectives: This study aims to analyze the impact of Wharton's jelly mesenchymal stem cell (WJ-MSC)-derived exosomes on HSC activation induced by PDGF during liver fibrosis. Methods: Hepatic stellate cells-T6 cells were treated with PDGF-BB for 24 hours to induce activation, followed by treatment with varying concentrations of WJ-MSC-derived exosomes (0, 25, and 50 µg/mL) for another 24 hours. The effects of exosome treatment on HSC activation were evaluated through flow cytometry, differentiation assays, dynamic light scattering (DLS), transmission electron microscopy (TEM), RT-PCR, and western blot analysis. Results: Our study yields promising results, highlighting the potential therapeutic effects of WJ-MSC-derived exosomes on liver fibrosis. The dose-dependent decrease in fibrotic markers such as α-SMA, COLA1, and phosphorylated AKT protein in PDGF-BB-treated HSC-T6 cells suggests that WJ-MSC exosomes exert an anti-fibrotic effect by inhibiting HSC activation. Conclusions: These findings suggest that exosomes derived from WJ-MSCs hold therapeutic promise for liver fibrosis treatment by targeting key pathways involved in HSC activation and fibrogenesis. Further investigation into the underlying mechanisms of this anti-fibrotic effect and the potential clinical applications of WJ-MSC-derived exosomes in liver fibrosis management is warranted.

MiR-335-3p attenuates transforming growth factor beta 1-induced fibrosis by suppressing Thrombospondin 1.

Pulmonary fibrosis is characterized by excessive extracellular matrix (ECM) accumulation caused by detrimental stimuli. The progressive impairment in lung functions is chronic and highly fatal, presenting itself as a global health challenge. Because of the lack of efficacious treatments, the underlying mechanism should be investigated. The progression of fibrosis involves transforming growth factor-beta 1 (TGF-β1), which accelerates ECM production via epithelial-mesenchymal transition and cell invasion. As microRNAs (miRNAs) serve as regulators of disease development and progression, this study aimed to investigate the interaction of miRNAs and target genes that could contribute to pulmonary fibrosis when exposed to TGF-β1. Differentially expressed mRNA and miRNA were identified in respiratory epithelial cells via transcriptome analysis by using the constructed TGF-β1-induced fibrosis model. Our results revealed a significant increase in the expression of thrombospondin 1 (THBS1), which participates in TGF-β1 activation, where THBS1 was identified as a core gene in protein interactions analyzed through bioinformatics. The expression of miR-335-3p, which targets 3'-UTR of THBS1, substantially decreased upon TGF-β1 treatment. The TGF-β1 downstream signal was suppressed by inhibiting the interaction between TGF-β1 and THBS1, consequently alleviating fibrosis. When the miR-335-3p mimic was transfected in TGF-β1-treated respiratory epithelial cells, THBS1 and fibrosis markers were downregulated, while the introduction of miR-335-3p inhibitor exhibited a reverse phenomenon. Our findings demonstrated that TGF-β1 exposure to respiratory epithelial cells led to a decrease in miR-335-3p expression, resulting in the upregulation of THBS1 and ultimately exacerbating fibrosis. This study provides insights into TGF-β1-induced pulmonary fibrosis, suggesting new therapeutic targets and mechanisms.

Rutaecarpine alleviates inflammation and fibrosis by targeting CK2α in diabetic nephropathy

Diabetic nephropathy (DN) is one of the serious microvascular complications of diabetes mellitus. During the progression of DN, the proliferation of glomerular mesangial cells (GMCs) leads to the deposition of excessive extracellular matrix (ECM) in the mesangial region, eventually resulting in glomerulosclerosis. Rutaecarpine (Rut), an alkaloid found in the traditional Chinese medicinal herb Fructus Evodiae (Euodia rutaecarpa (Juss.) Benth.), has many biological activities. However, its mechanism of action in DN remains unknown. This study used db/db mice and high glucose (HG)-treated mouse mesangial cells (SV40 MES-13) to evaluate the protective effects of Rut and underlying mechanisms on GMCs in DN. We found that Rut alleviated urinary albumin and renal function and significantly relieved renal pathological damage. In addition, Rut decreased the ECM production, and renal inflammation and suppressed the activation of TGF-β1/Smad3 and NF-κB signaling pathways in vitro and in vivo. Protein kinase CK2α (CK2α) was identified as the target of Rut by target prediction, molecular docking, and cellular thermal shift assay (CETSA), and surface plasmon resonance (SPR). Furthermore, Rut could not continue to play a protective role in HG-treated SV40 cells after silencing CK2α. In summary, this study is the first to find that Rut can suppress ECM production and inflammation in HG-treated SV40 cells by inhibiting the activation of TGF-β1/Smad3 and NF-κB signaling pathways and targeting CK2α. Thus, Rut can potentially become a novel treatment option for DN.

Exogenous S1P via S1P receptor 2 induces CTGF expression through Src-RhoA-ROCK-YAP pathway in hepatic stellate cells.

Hepatic fibrosis, a prevalent chronic liver condition, involves excessive extracellular matrix production associated with aberrant wound healing. Hepatic stellate cells (HSCs) play a pivotal role in liver fibrosis, activated by inflammatory factors such as sphingosine 1-phosphate (S1P). Despite S1P's involvement in fibrosis, its specific role and downstream pathway in HSCs remain controversial. In this study, we investigated the regulatory role of S1P/S1P receptor (S1PR) in Hippo-YAP activation in both LX-2 cell lines and primary HSCs. Real-time PCR, western blot, pharmacological inhibitors, siRNAs, and Rho activity assays were adopted to address the molecular mechanisms of S1P mediated YAP activation. Serum and exogenous S1P significantly increased the expression of YAP target genes in HSCs. Pharmacologic inhibitors and siRNA-mediated knockdowns of S1P receptors showed S1P receptor 2 (S1PR2) as the primary mediator for S1P-induced CTGF expression in HSCs. Results using siRNA-mediated knockdown, Verteporfin, and Phospho-Tag immunoblots showed that S1P-S1PR2 signaling effectively suppressed the Hippo kinases cascade, thereby activating YAP. Furthermore, S1P increased RhoA activities in cells and ROCK inhibitors effectively blocked CTGF induction. Cytoskeletal-perturbing reagents were shown to greatly modulate CTGF induction, suggesting the important role of actin cytoskeleton in S1P-induced YAP activation. Exogeneous S1P treatment was enough to increase the expression of COL1A1 and α-SMA, that were blocked by YAP specific inhibitor. Our data demonstrate that S1P/S1PR2-Src-RhoA-ROCK axis leads to Hippo-YAP activation, resulting in the up-regulation of CTGF, COL1A1 and α-SMA expression in HSCs. Therefore, S1PR2 may represent a potential therapeutic target for hepatic fibrosis.

Extracellular Vesicle-Associated Neutrophil Elastase Activates Hepatic Stellate Cells and Promotes Liver Fibrogenesis via ERK1/2 Pathway.

Liver fibrosis associated with increased mortality is caused by activation of hepatic stellate cells and excessive production and accumulation of extracellular matrix in response to fibrotic insults. It has been shown that in addition to liver inflammation, systemic inflammation also contributes to liver fibrogenesis. A deeper understanding of mechanisms that control liver fibrotic response to intra- and extra-hepatic inflammation is essential to develop novel clinical strategies against this disease. Extracellular vesicles (EV) have been recognized as immune mediators that facilitate activation of hepatic stellate cells. In inflammatory diseases, activated neutrophils release neutrophil elastase (NE) bound to EV, which has been identified as a significant contributor to inflammation by promoting immune cell activation. Here, we aimed to explore the role of inflammation derived plasma EV-associated NE in liver fibrogenesis and its potential mechanisms. We show EV-associated NE induces activation, proliferation and migration of hepatic stellate cells by promoting activation of the ERK1/2 signaling pathway. This effect did not occur through EV without surface NE, and Sivelestat, a NE inhibitor, inhibited activation of the ERK1/2 signaling pathway mediated by EV-associated NE. Moreover, we found plasma EV-associated NE increases deposition of collagen1 and α-smooth muscle actin in the liver of a mouse model of liver fibrosis (Mdr2-/-). Notably, this effect does not occur in control mice without preexisting liver disease. These data suggest that EV-associated NE is a pro-fibrogenic factor for hepatic stellate cell activation via the ERK1/2 signaling pathway in pre-existing liver injuries. Inhibition of the plasma EV-associated NE in inflammatory conditions may be a therapeutic target for liver fibrosis in patients with inflammatory diseases.

Pyruvate metabolism dictates fibroblast sensitivity to GLS1 inhibition during fibrogenesis.

Fibrosis is a chronic disease characterized by excessive extracellular matrix production, which leads to disruption of organ function. Fibroblasts are key effector cells of this process, responding chiefly to the pleiotropic cytokine transforming growth factor-β1 (TGF-β1), which promotes fibroblast to myofibroblast differentiation. We found that extracellular nutrient availability profoundly influenced the TGF-β1 transcriptome of primary human lung fibroblasts and that biosynthesis of amino acids emerged as a top enriched TGF-β1 transcriptional module. We subsequently uncovered a key role for pyruvate in influencing glutaminase (GLS1) inhibition during TGF-β1-induced fibrogenesis. In pyruvate-replete conditions, GLS1 inhibition was ineffective in blocking TGF-β1-induced fibrogenesis, as pyruvate can be used as the substrate for glutamate and alanine production via glutamate dehydrogenase (GDH) and glutamic-pyruvic transaminase 2 (GPT2), respectively. We further show that dual targeting of either GPT2 or GDH in combination with GLS1 inhibition was required to fully block TGF-β1-induced collagen synthesis. These findings embolden a therapeutic strategy aimed at additional targeting of mitochondrial pyruvate metabolism in the presence of a glutaminolysis inhibitor to interfere with the pathological deposition of collagen in the setting of pulmonary fibrosis and potentially other fibrotic conditions.

Comprehensive Insights into Keloid Pathogenesis and Advanced Therapeutic Strategies.

Keloid scars, characterized by abnormal fibroproliferation and excessive extracellular matrix (ECM) production that extends beyond the original wound, often cause pruritus, pain, and hyperpigmentation, significantly impacting the quality of life. Keloid pathogenesis is multifactorial, involving genetic predisposition, immune response dysregulation, and aberrant wound-healing processes. Central molecular pathways such as TGF-β/Smad and JAK/STAT are important in keloid formation by sustaining fibroblast activation and ECM deposition. Conventional treatments, including surgical excision, radiation, laser therapies, and intralesional injections, yield variable success but are limited by high recurrence rates and potential adverse effects. Emerging therapies targeting specific immune pathways, small molecule inhibitors, RNA interference, and mesenchymal stem cells show promise in disrupting the underlying mechanisms of keloid pathogenesis, potentially offering more effective and lasting treatment outcomes. Despite advancements, further research is essential to fully elucidate the precise mechanisms of keloid formation and to develop targeted therapies. Ongoing clinical trials and research efforts are vital for translating these scientific insights into practical treatments that can markedly enhance the quality of life for individuals affected by keloid scars.

TWIST1+FAP+ fibroblasts in the pathogenesis of intestinal fibrosis in Crohn's disease.

Intestinal fibrosis, a severe complication of Crohn's disease (CD), is characterized by excessive extracellular matrix (ECM) deposition and induces intestinal strictures, but there are no effective antifibrosis drugs available for clinical application. We performed single-cell RNA sequencing (scRNA-Seq) of fibrotic and nonfibrotic ileal tissues from patients with CD with intestinal obstruction. Analysis revealed mesenchymal stromal cells (MSCs) as the major producers of ECM and the increased infiltration of its subset FAP+ fibroblasts in fibrotic sites, which was confirmed by immunofluorescence and flow cytometry. Single-cell transcriptomic profiling of chronic dextran sulfate sodium salt murine colitis model revealed that CD81+Pi16- fibroblasts exhibited transcriptomic and functional similarities to human FAP+ fibroblasts. Consistently, FAP+ fibroblasts were identified as the key subtype with the highest level of ECM production in fibrotic intestines. Furthermore, specific knockout or pharmacological inhibition of TWIST1, which was highly expressed by FAP+ fibroblasts, could significantly ameliorate fibrosis in mice. In addition, TWIST1 expression was induced by CXCL9+ macrophages enriched in fibrotic tissues via IL-1β and TGF-β signal. These findings suggest the inhibition of TWIST1 as a promising strategy for CD fibrosis treatment.

Serum deprivation protein response intervenes in the proliferation, motility, and extracellular matrix production in keloid fibroblasts by blocking the amplification of TGF-β1/SMAD signal cascade via ERK1/2

Keloid formation has been linked to abnormal fibroblast function, such as excessive proliferation and extracellular matrix (ECM) production. Serum deprivation protein response (SDPR) is a crucial regulator of cellular function under diverse pathological conditions, yet its role in keloid formation remains unknown. The current work investigated the function of SDPR in regulating the proliferation, motility, and ECM production of keloid fibroblasts (KFs), as well as to decipher the mechanisms involved. Analysis of RNA sequencing data from the GEO database demonstrated significant down-regulation of SDPR in KF compared to normal fibroblasts (NFs). This down-regulation was also observed in clinical keloid specimens and isolated KFs. Overexpression of SDPR suppressed the proliferation, motility, and ECM production of KFs, while depletion of SDPR exacerbated the enhancing impact of TGF-β1 on the proliferation, motility, and ECM production of NFs. Mechanistic studies revealed that SDPR overexpression repressed TGF-β/Smad signal cascade activation in KFs along with decreased levels of phosphorylated Samd2/3, while SDPR depletion exacerbated TGF-β/Smad activation in TGF-β1-stimulated NFs. SDPR overexpression also repressed ERK1/2 activation in KFs, while SDPR depletion exacerbated ERK1/2 activation in TGF-β1-stimulated NFs. Inhibition of ERK1/2 abolished SDPR-depletion-induced TGF-β1/Smad activation, cell proliferation, motility, and ECM production in NFs. In conclusion, SDPR represses the proliferation, motility, and ECM production in KFs by blocking the TGF-β1/Smad pathway in an ERK1/2-dependent manner. The findings highlight the role of SDPR in regulating abnormal behaviors of fibroblasts associated with keloid formation and suggest it as a potential target for anti-keloid therapy development.

Mendelian randomization reveals interactions of the blood proteome and immunome in mitral valve prolapse

BackgroundMitral valve prolapse (MVP) is a common heart disorder characterized by an excessive production of proteoglycans and extracellular matrix in mitral valve leaflets. Large-scale genome-wide association study (GWAS) underlined that MVP is heritable. The molecular underpinnings of the disease remain largely unknown.MethodsWe interrogated cross-modality data totaling more than 500,000 subjects including GWAS, 4809 molecules of the blood proteome, and genome-wide expression of mitral valves to identify candidate drivers of MVP. Data were investigated through Mendelian randomization, network analysis, ligand-receptor inference and digital cell quantification.ResultsIn this study, Mendelian randomization identify that 33 blood proteins, enriched in networks for immunity, are associated with the risk of MVP. MVP- associated blood proteins are enriched in ligands for which their cognate receptors are differentially expressed in mitral valve leaflets during MVP and enriched in cardiac endothelial cells and macrophages. MVP-associated blood proteins are involved in the renewal-polarization of macrophages and regulation of adaptive immune response. Cytokine activity profiling and digital cell quantification show in MVP a shift toward cytokine signature promoting M2 macrophage polarization. Assessment of druggability identify CSF1R, CX3CR1, CCR6, IL33, MMP8, ENPEP and angiotensin receptors as actionable targets in MVP.ConclusionsHence, integrative analysis identifies networks of candidate molecules and cells involved in immune control and remodeling of the extracellular matrix, which drive the risk of MVP.

Imaging of Cardiac Fibrosis: An Update, From the AJR Special Series on Imaging of Fibrosis.

Myocardial fibrosis (MF) is defined as excessive production and deposition of extra-cellular matrix proteins that result in pathologic myocardial remodeling. Three types of MF have been identified: replacement fibrosis from tissue necrosis, reactive fibrosis from myocardial stress, and infiltrative interstitial fibrosis from progressive deposition of nondegradable material such as amyloid. Although echocardiography, nuclear medicine, and CT play important roles in the assessment of MF, MRI is pivotal in the evaluation of MF, with the late gadolinium enhancement (LGE) technique used as a primary end point. The LGE technique focuses on the pattern and distribution of gadolinium accumulation in the myocardium and assists in the diagnosis and establishment of the cause of both ischemic and nonischemic cardiomyopathy. LGE MRI also aids prognostication and risk stratification. In addition, LGE MRI is used to guide the management of patients considered for ablation for arrhythmias. Parametric mapping techniques, including T1 mapping and extracellular volume measurement, allow detection and quantification of diffuse fibrosis, which may not be detected by LGE MRI. These techniques also allow monitoring of disease progression and therapy response. This review provides an update on the imaging of MF, including prognostication and risk stratification tools, electrophysiologic considerations, and disease monitoring.

Ethyl Pyruvate Decreases Collagen Synthesis and Upregulates MMP Activity in Keloid Fibroblasts and Keloid Spheroids.

Keloids, marked by abnormal cellular proliferation and excessive extracellular matrix (ECM) accumulation, pose significant therapeutic challenges. Ethyl pyruvate (EP), an inhibitor of the high-mobility group box 1 (HMGB1) and TGF-β1 pathways, has emerged as a potential anti-fibrotic agent. Our research evaluated EP's effects on keloid fibroblast (KF) proliferation and ECM production, employing both in vitro cell cultures and ex vivo patient-derived keloid spheroids. We also analyzed the expression levels of ECM components in keloid tissue spheroids treated with EP through immunohistochemistry. Findings revealed that EP treatment impedes the nuclear translocation of HMGB1 and diminishes KF proliferation. Additionally, EP significantly lowered mRNA and protein levels of collagen I and III by attenuating TGF-β1 and pSmad2/3 complex expression in both human dermal fibroblasts and KFs. Moreover, metalloproteinase I (MMP-1) and MMP-3 mRNA levels saw a notable increase following EP administration. In keloid spheroids, EP induced a dose-dependent reduction in ECM component expression. Immunohistochemical and western blot analyses confirmed significant declines in collagen I, collagen III, fibronectin, elastin, TGF-β, AKT, and ERK 1/2 expression levels. These outcomes underscore EP's antifibrotic potential, suggesting its viability as a therapeutic approach for keloids.

Hypoxia in uterine fibroids: role in pathobiology and therapeutic opportunities.

Uterine fibroids are the most common tumors in females affecting up to 70% of women world-wide, yet targeted therapeutic options are limited. Oxidative stress has recently surfaced as a key driver of fibroid pathogenesis and provides insights into hypoxia-induced cell transformation, extracellular matrix pathophysiology, hypoxic cell signaling cascades, and uterine biology. Hypoxia drives fibroid tumorigenesis through (1) promoting myometrial stem cell proliferation, (2) causing DNA damage propelling transformation of stem cells to tumor initiating cells, and (3) driving excess extracellular matrix (ECM) production. Common fibroid-associated DNA mutations include MED12 mutations, HMGA2 overexpression, and Fumarate hydratase loss of function. Evidence suggests an interaction between hypoxia signaling and these mutations. Fibroid development and growth are promoted by hypoxia-triggered cell signaling via various pathways including HIF-1, TGFβ, and Wnt/β-catenin. Fibroid-associated hypoxia persists due to antioxidant imbalance, ECM accumulation, and growth beyond adequate vascular supply. Current clinically available fibroid treatments do not take advantage of hypoxia-targeting therapies. Growing pre-clinical and clinical studies identify ROS inhibitors, anti-HIF-1 agents, Wnt/β-catenin inhibition, and TGFβ cascade inhibitors as agents that may reduce fibroid development and growth through targeting hypoxia.

SEMA3B inhibits TGFβ-induced extracellular matrix protein production and its reduced levels are associated with a decline in lung function in IPF.

Idiopathic pulmonary fibrosis (IPF) is marked by the activation of fibroblasts, leading to excessive production and deposition of extracellular matrix (ECM) within the lung parenchyma. Despite the pivotal role of ECM overexpression in IPF, potential negative regulators of ECM production in fibroblasts have yet to be identified. Semaphorin class 3B (SEMA3B), a secreted protein highly expressed in lung tissues, has established roles in axonal guidance and tumor suppression. However, the role of SEMA3B in ECM production by fibroblasts in the pathogenesis of IPF remains unexplored. Here, we show the downregulation of SEMA3B and its cognate binding receptor, neuropilin 1 (NRP1), in IPF lungs compared with healthy controls. Notably, the reduced expression of SEMA3B and NRP1 is associated with a decline in lung function in IPF. The downregulation of SEMA3B and NRP1 transcripts was validated in the lung tissues of patients with IPF, and two alternative mouse models of pulmonary fibrosis. In addition, we show that transforming growth factor-β (TGFβ) functions as a negative regulator of SEMA3B and NRP1 expression in lung fibroblasts. Furthermore, we demonstrate the antifibrotic effects of SEMA3B against TGFβ-induced ECM production in IPF lung fibroblasts. Overall, our findings uncovered a novel role of SEMA3B in the pathogenesis of pulmonary fibrosis and provided novel insights into modulating the SEMA3B-NRP1 axis to attenuate pulmonary fibrosis.NEW & NOTEWORTHY The excessive production and secretion of collagens and other extracellular matrix proteins by fibroblasts lead to the scarring of the lung in severe fibrotic lung diseases. This study unveils an antifibrotic role for semaphorin class 3B (SEMA3B) in the pathogenesis of idiopathic pulmonary fibrosis. SEMA3B functions as an inhibitor of transforming growth factor-β-driven fibroblast activation and reduced levels of SEMA3B and its receptor, neuropilin 1, are associated with decreased lung function in idiopathic pulmonary fibrosis.

Unmetabolized folic acid and organ fibrosis: Are they nefarious partners?

Recent publications raise the possibility that folic acid (FA), specifically unmetabolized folic acid (UMFA), might promote the progression of organ fibrosis via signaling through folate receptors, leading to excessive extracellular matrix production by myofibroblasts and other cell types. Clinical research over the past two decades adds credence to this largely unexplored contention. FA is a synthetic form of folate, first made in 1945, that has been added to the food supply in the US since 1998 to decrease neural tube defects; subsequently, other countries have followed suit. Notably, synthetic FA, compared to natural dietary folates, is metabolized differently, and potentially activates cellular signaling pathways, leading to fibrosis progression. Although FA food supplementation programs have resulted in a roughly 2-fold increase in serum folate concentrations and a decrease in the prevalence of neural tube defects, other concerns have surfaced. As such, due to the incomplete metabolism of ingested FA, before it can enter cellular processes, most individuals exhibit concentrations of unmetabolized folic acid (UMFA) in the circulation. We hypothesize that it is UMFA, but not natural occurring food folates, which in part promotes the progression of organ fibrosis in many systems. We feel the issue is relevant since organ fibrosis is involved in nearly half of all mortality in industrialized nations. Finally, this proposed nexus of UMFA and organ fibrosis might have preventive and therapeutic implications, and more research is needed on the topic.

Systems-based identification of the Hippo pathway for promoting fibrotic mesenchymal differentiation in systemic sclerosis

Systemic sclerosis (SSc) is a devastating autoimmune disease characterized by excessive production and accumulation of extracellular matrix, leading to fibrosis of skin and other internal organs. However, the main cellular participants in SSc skin fibrosis remain incompletely understood. Here using differentiation trajectories at a single cell level, we demonstrate a dual source of extracellular matrix deposition in SSc skin from both myofibroblasts and endothelial-to-mesenchymal-transitioning cells (EndoMT). We further define a central role of Hippo pathway effectors in differentiation and homeostasis of myofibroblast and EndoMT, respectively, and show that myofibroblasts and EndoMTs function as central communication hubs that drive key pro-fibrotic signaling pathways in SSc. Together, our data help characterize myofibroblast differentiation and EndoMT phenotypes in SSc skin, and hint that modulation of the Hippo pathway may contribute in reversing the pro-fibrotic phenotypes in myofibroblasts and EndoMTs.

An In Silico Study of Transforming Growth Factor-β Inhibitors: A Potential Target for Diabetic Nephropathy Treatment with Active Compounds from the Active Fraction of Physalis angulata.

Transforming growth factor beta (TGF-β) initiates epithelial-mesenchymal transition (EMT) in tubular and glomerular epithelial cells, resulting in excessive production and deposition of extracellular matrix through its interaction with TGF-β receptors, which play a crucial role in TGF-β signaling involving two receptor types, namely TGF-β type I (TβRI) and type II (TβRII). EMT contributes to the pathogenesis of interstitial renal fibrosis, a marker of end-stage kidney disease. This study aimed to identify the bioactive compounds in the active fraction of P. angulata and evaluate their ability to inhibit the TGF-β activity and their potential as drug candidates. The active components in the active fraction of P. angulata were analyzed using gas chromatography-mass spectrometry (GC-MS). The bioactive compound structures were obtained from the PubChem database, while the protein targets, TβRI and TβRII, were retrieved from the Protein Data Bank (PDB). The molecular docking analyses were performed using PyRx 0.8 and Discovery Studio. SwissADME was used to evaluate ligand properties and druglikeness. Three dominant active compounds were identified, namely palmitic acid, campesterol, and stigmasterol. In silico studies demonstrated strong energy bonds existed between TβRI and palmitic acid, campesterol, stigmasterol, and SB431542 with binding energy values of -5.7, -10, -9.4, and -10.9 kcal/mol, respectively. Similarly, they strongly bound to TβRII with binding energy values of -5.2, -7.1, -7.5, and -6.1 kcal/mol, respectively. All compounds meet Lipinski's criteria for druglikeness. Among the identified active compounds, campesterol exhibited the highest affinity for TβRI, while stigmasterol exhibited a strong affinity for TβRII. These findings suggested that the three compounds have potential as drug candidates.