Search Results (922)

Background and Objectives: TAM receptors—Tyro3, Axl, and Mer—and their ligand Growth Arrest-Specific 6 (Gas6) represent a pleiotropic system implicated in fibrosis. Increased Gas6 and Axl expression have previously been observed in lung samples and fibroblast cultures from Idiopathic Pulmonary Fibrosis (IPF) patients. The study explored the contribution of Gas6/TAM system in fibrosis development and the impact of its pharmacological inhibition in fibroblasts. Materials and Methods: IPF fibroblasts (IPF FBs) and control human pulmonary fibroblasts (HPFs) were treated with R428 (Axl-specific inhibitor), LDC1267 (TAM inhibitor), or Nintedanib (an IPF-approved drug) to evaluate the influence of these drugs on cell proliferation, migration, and the expression of pro-inflammatory and pro-fibrotic genes. Fibroblast-to-myofibroblast differentiation was induced by TGF-β. The impact of IPF FBs and HPF on macrophage polarization was investigated through a co-culture of fibroblasts with monocyte-derived macrophages, with the further gene expression analysis of markers of the M1 (pro-inflammatory) or M2 (pro-fibrotic) polarization forms. Results: Cell proliferation was monitored in fibroblasts treated with TGF-β, the drugs, and their combination. In the presence of LDC1267 and Nintedanib, minor differences in cell confluence were detected between IPF FBs and HPFs; R428 (1 μM) seemed to have a higher inhibitory impact on IPF FBs. Regarding cell migration, the fibroblasts treated with LDC1267 exhibited slower wound closure. R428 treatment led to a relative wound closure of 76% in HPFs but only 56% in IPF FBs (60 h). R428 (1 μM) significantly reduced the expression of the pro-fibrotic markers ACTA2, COL1A1, and FN1 in HPFs and IPF FBs compared to TGF-β treatment. HPFs and IPF FBs co-cultured with monocyte-derived macrophages demonstrated a significantly increased expression of MRC1 while the expression of FN1, TNFα, and CXCL10 was moderately increased. Conclusions: These findings suggest that R428 and LDC1267 modulate the proliferation, migration, and gene expression of activated fibroblasts via TAM signaling. Fibroblast-mediated effects on macrophage polarization underscore the relevance of intercellular crosstalk in fibrotic disease. Full article

Myofibroblasts drive wound healing and fibrotic disease through generation of contractile force to promote wound closure and production of matrix proteins to generate scar tissue. Platelets secrete many pro-wound healing molecules, including cytokines and growth factors. We previously reported that inorganic polyphosphate, secreted by activated platelets, is chemotactic for fibroblasts and induces a myofibroblast phenotype. Using NIH-3T3 cells and primary human fibroblasts, we examined the impact of inhibitors of cell-surface receptors and intracellular signaling molecules on polyphosphate-induced myofibroblast differentiation. We now report that polyphosphate-induced differentiation of fibroblasts to myofibroblasts occurs through a signaling pathway mediated by the receptor for advanced glycation end products (RAGE) and nuclear factor kappa B (NFκB) transcription factor. Inhibition of these signaling components ablated the effects of polyphosphate on fibroblasts. Platelet releasates also induced NFκB signaling and myofibroblast differentiation. Blocking the polyphosphate content of platelet releasates with a biocompatible polyP inhibitor rendered the releasates unable to induce myofibroblast differentiation. These results identify a cell-surface receptor and intracellular transcription factor utilized by platelet polyphosphate to promote wound healing through myofibroblast differentiation and may provide targets for promoting wound healing or altering the disease progression of fibrosis. Full article

Angiotensin II (AngII), the primary effector of the renin-angiotensin system, is essential for maintaining blood pressure and fluid-electrolyte homeostasis. However, elevated AngII levels are a feature of disease conditions such as heart failure and chronic kidney disease, where it is associated with pathological tissue remodeling and fibrosis. AngII-mediated fibrosis has been documented in multiple organs and is characterized by fibroblast expansion, myofibroblast differentiation, and excessive extracellular matrix deposition. Periostin has recently emerged as a marker of fibroblast activation. Notably, periostin expression is highly upregulated during fibrotic remodeling in the kidney and lung, which is strongly linked with impaired organ function. While AngII-induced activation of periostin-lineage (Postn^Lin) cells is well established in the heart, the temporal dynamics of Postn^Lin activation in response to AngII infusion in the lung and kidney remain unexplored. Here, we used a Postn-MerCreMer lineage-tracing approach, combined with continuous AngII infusion over an experimental period of one week and two weeks to assess Postn^Lin responses in lung and kidney. Our findings reveal a progressive activation of Postn^Lin cells in both organs, characterized by myofibroblast phenotype, together with increased collagen deposition and macrophage infiltration. These results highlight the potential of Postn^Lin fibroblasts as a key effector of AngII-mediated tissue remodeling and fibrosis in the lung and kidney. Full article

Corneal fibrosis, a significant source of visual impairment, can result from keratocyte-to-myofibroblast transdifferentiation during wound healing. This study investigated the antifibrotic role of 1,25-dihydroxyvitamin D₃ (1,25 Vit D) and the lesser-known vitamin D, 24,25-dihydroxyvitamin D₃ (24,25 Vit D), in human and mouse corneal stromal cells (HSCs and MSCs) and in a Vit D receptor knockout (VDR KO) mouse model. Cells were treated with TGF-β1 ± Vit D metabolites and the expression of fibrotic and antifibrotic genes and proteins was evaluated. Both metabolites significantly reduced α-smooth muscle actin levels in HSCs, MSCs and organ-cultured mouse corneas (p < 0.05). They also upregulated the mRNA expression of BMP2, BMP6, BMPR2, and TGF-β3, as well as the protein expression of BMP6 and TGF-β3. VDR KO corneas subjected to alkali injury exhibited increased fibrotic responses and reduced CD45+ immune cell infiltration compared to wild-type controls. Notably, 24,25 Vit D exerted antifibrotic effects even in VDR KO cells, and the alternative 24,25 Vit D receptor FAM57B was expressed in all corneal cell layers. These results reveal consistent antifibrotic effects of both 1,25 and 24,25 Vit D across species, support the existence of VDR-independent mechanisms in the cornea, and offer new insights into potential therapeutic strategies for preventing corneal fibrosis. Full article

Background: Post-traumatic joint contracture (PTJC) remains one of the most prevalent and challenging complications arising from musculoskeletal trauma or surgical intervention. Conventional treatment modalities are largely reactive and address symptoms after onset, yet provide limited efficacy once contracture has developed. In contrast, pharmacological strategies targeting the underlying inflammatory and fibrotic pathways offer a promising strategy for preventing the development of PTJC altogether. Methods: A total of 26 male Sprague Dawley rats underwent standardized knee trauma followed by immobilization for a duration of two weeks. Rats were randomized into two groups. The experimental group (n = 13) received bosentan at a dosage of 50 mg/kg twice daily throughout the immobilization period. The control group (n = 13) received a placebo instead. Joint mobility was quantitatively assessed by measuring the contracture angle (CA) and resistance to extension. In addition, posterior joint capsule tissues were harvested for histological analysis and subjected to quantitative PCR (qPCR) to quantify the expression of profibrotic genes, including α-Sma, Il-6, Tgf-β1, Nfκ-b, Ctgf. Results: Bosentan had no relevant effect on the biomechanics of the contracture compared to the placebo group. The contracture angle was comparable between the groups (86.8° ± 14.1°, 84.8° ± 11.1°). Similarly, the force required to achieve knee joint extension was comparable between the groups. Gene expression analysis also provided no evidence of reduced expression of pro-inflammatory or profibrotic genes. Histological assessments revealed no change in the absolute or relative number of myofibroblasts, or in the number of vessels, in the posterior joint capsules of the rats treated with bosentan. Compared to the control group, the number of myofibroblasts significantly increased in both the bosentan and control groups (p < 0.001, one-way ANOVA). Conclusions: Bosentan’s purported antifibrotic properties do not appear to confer a preventative effect on the development of PTJC. These findings suggest that, despite its potential in modulating fibrosis, bosentan does not mitigate the progression of the fibrotic condition. Furthermore, the involvement of endothelin-1 (ET-1) in the pathophysiology of PTJC remains yet to be fully understood, warranting further investigation. Full article

Bulbine species (Asphodelaceae) are routinely used in many African communities to treat various dermatological disorders, including wounds, due to their relative accessibility, affordability, safety records, and reported efficacies. However, these reported biological activities lack robust empirical evidence and well-validated cellular mechanisms for plausible applications. Hence, this review was aimed at investigating the bioactive compounds of Bulbine species linked to their cellular wound healing attributes, their toxicity, and cytotoxicity. A detailed literature search was conducted using Web of Science, Google scholar, and PubMed, followed by Scopus and VOSviewer (version 1.6.20) bibliographic analyses. Bulbine frutescens (L.) Willd. and Bulbine natalensis Baker safely mediate tissue healing and coagulation cascade as adaptogens and cytotoxic agents. The wound healing activities of the Bulbine species were linked to the synergistic wound healing or tissue repair properties of bioactive compounds (such as saponins, terpenoids, luteolin, and apigenin) via the expression of collagen type-I, alpha-2 (COL1A2) gene, collagen III, increase in the wound tensile strength, and anti-cytokine interleukin-10 (IL-10) mRNA. Bulbine species were also reported to contain specialised biomarker compounds (such as naphthoquinones, bulbine-emodin, and aloe-emodin) which mediate the activation of hydroxyproline, Aryl Hydrocarbon Receptor, transforming growth factor beta—β1 (TGFβ1), and the suppressor of mothers against decapentaplegic proteins (SMAD), which ultimately induce tissue granulation, myofibroblast differentiation, re-epithelialization, higher protein complexes, and scar tissue formations. These findings give credence to the wound healing therapeutic potential of Bulbine species. However, additional clinical studies are necessary to further ascertain the reported efficacies of Bulbine species’ bioactive principles, their overall safety, and the underlying cellular mechanisms involved in the wound healing process and carcinogenesis. Full article

Galectins represent a family of widely expressed lectins that have the ability to bind β-galactoside in modulating “cell-to-cell” and “cell-to-matrix” interactions in all organisms. These proteins are expressed in many inflammatory cells, such as macrophages, and depending on the inflammatory environment, they promote pro-inflammatory or anti-inflammatory responses. Galectin-3 (Gal-3) is predominantly located in the cytoplasm, but, as noted, it has also been detected in the nucleus, on the cell surface and in the extracellular environment, which indicates the multifunctionality of this molecule. It has been shown in many studies that Gal-3 is involved in immune regulation, fibrosis, and tissue remodeling, making it an important player in disorders such as inflammatory bowel disease (IBD), non-alcoholic steatohepatitis (NASH), and liver fibrosis. In IBD, this protein is associated with activation of the NLRP3 inflammasome, contributing to chronic intestinal inflammation. Also, in primary biliary cholangitis and autoimmune hepatitis, Gal-3 potentiate development of fibrosis through fibroblast-to-myofibroblast transition and extracellular matrix deposition, while in liver fibrosis, it is upregulated in hepatic stellate cells and macrophages, promoting fibrosis and inflammation. Studies show that Gal-3 inhibition reduces fibrosis and inflammation, making it a promising therapeutic target. Full article

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterized by aberrant fibroblast activation, lysosomal dysfunction, and cellular senescence. Transcriptomic analyses have identified ependymin-related 1 (EPDR1) as a fibroblast-enriched gene in IPF, but its biological function remains unclear. EPDR1 expression was assessed in lung fibroblasts, lung tissues, bronchoalveolar lavage fluid (BALF), and serum from IPF patients and controls using qPCR, Western blotting, ELISA, and immunohistochemistry. Lysosomal function, autophagic flux, and senescence markers were analyzed in primary fibroblasts following siRNA-mediated EPDR1 knockdown. EPDR1 was significantly upregulated in IPF-derived fibroblasts and localized to fibrotic regions enriched with α-SMA⁺, COL1A1⁺, and FN1⁺ myofibroblasts of IPF-derived lung tissues. EPDR1 levels were markedly elevated in the BALF and serum of IPF patients and correlated with increased mortality. IPF fibroblasts exhibited reduced lysosomal acidification and impaired autophagic flux, indicated by p62 and LC3B accumulation. EPDR1 knockdown restored lysosomal function; enhanced autophagic degradation; and reduced senescence markers, including p21, p16, and SA-β-gal activity. EPDR1 drives lysosomal dysfunction and fibroblast senescence in IPF. Its elevated expression in lung tissue and biological fluids, together with its association with prognosis, highlights EPDR1 as a potential biomarker and therapeutic target in IPF. Full article

The secretome of mesenchymal stromal cells (MSCs) can efficiently stimulate regeneration and therefore is a tempting remedy for “cell-free cellular therapy”. However, the usage of primary MSC cultures as secretome producers for translation studies has obvious obstacles, including the rapid aging of MSC cultures, the need for a large number of verified donors, and donor-to-donor variability of secretome content. MSCs immortalization makes it possible to overcome those limitations and to obtain secretome-producing cultures with a prolonged lifetime. However, the efficacy and safety of such secretomes are critical issues that limit their usage as therapeutic agents. In this study, we tested in large detail how the immortalization of MSC cultures affects the content, biological activity and safety of their secretome. MSCs immortalization via the overexpression of human TERT gene does not significantly alter the qualitative and quantitative composition of their secretome or its activity according to the results of proteomic analysis, ELISA, qPCR and functional tests in vitro. Moreover, we have demonstrated that the secretome of immortalized MSCs does not contain detectable amounts of telomerase and does not possess any transforming activity. Altogether, our data suggest that immortalized MSC cultures may become a reliable source for obtaining standardized active secretome in large-scale quantities for clinical use. Full article

Introduction: Pseudoangiomatous stromal hyperplasia (PASH) is a benign breast lesion characterized by stromal myofibroblast proliferation forming slit-like pseudoangiomatous spaces. Although most frequently diagnosed in premenopausal women, it has also been reported in adolescent girls, where it may present as a rapidly enlarging mass that mimics fibroadenoma or phyllodes tumor. The pathogenesis is thought to be hormonally influenced, particularly by progesterone, with a possible role for estrogen. Case Report: We report the case of a 14-year-old girl who presented with a painless, rapidly growing mass in the left breast, first noticed approximately six months earlier. Clinical examination revealed a mobile lesion about 10 cm in diameter without skin changes, lymphadenopathy, or nipple discharge. Ultrasound and MRI demonstrated a large, well-circumscribed solid tumor (10.4 × 11.2 × 4.2 cm³) displacing normal breast tissue but without infiltration; both were classified as BI-RADS 4. Given the tumor size, diagnostic uncertainty, and potential risk of a non-representative core needle biopsy, a decision was made to proceed with primary radical excision. The mass was completely removed with preservation of the glandular tissue. Histopathology confirmed PASH, described macroscopically as a solid, gray–yellow, encapsulated tumor and microscopically as slit-like spaces lined by spindle cells (CD34+, CD31–). Postoperatively, the breast gradually regained symmetry with the contralateral side, and at 14 months of follow-up, no recurrence was observed. Conclusions: PASH, although benign, may present as a large breast tumor in adolescents and clinically mimic both benign and malignant lesions. Histological evaluation based on an adequately performed biopsy is crucial for accurate diagnosis. Complete excision with capsule preservation is recommended to minimize the risk of recurrence. In adolescents, a watchful waiting approach after surgery may be beneficial, as breast tissue often remodels and regains symmetry spontaneously, reducing the need for reconstructive procedures. This case underscores the importance of individualized diagnostic and therapeutic strategies in managing rare benign breast lesions in pediatric patients. Full article

This review covers the roles of cartilage oligomeric matrix protein (COMP), an established biomarker of cartilage breakdown in pathological tissues in osteoarthritis, and in emerging areas in extracellular matrix and vascular remodeling associated with trauma, fibrosis and cancer. COMP is produced by chondrocytes, tenocytes, myofibroblasts, and in some specialized tissue contexts, endothelial and vascular smooth muscle cells. COMP expression by tendon and cartilage cells is sensitive to weight bearing and tensional mechanical stimulation. Vascular smooth muscle cells are sensitive to shear forces which regulate COMP expression in vascular tissues in atherosclerosis and in carotid stenosis. COMP is a multivalent bridging molecule that stabilizes tissues. It facilitates the signaling of TGF-β and BMP-2 in chondrogenesis, osteogenesis, tissue fibrosis, vascular and ECM remodeling and tumor development by providing a multimeric environment through which growth factor binding and receptor activation can occur. Engineered COMP proteins have been used as molecular templates in the development of chimeric therapeutic proteins of potential application in repair biology. Tie2 (Angiopoietin-1 receptor, Tyrosine-protein kinase receptor TEK), when activated by an engineered COMP-inspired angiopoietin-2 pentamer, is a potent angiogenic molecule of obvious application in wound healing. COMP’s multifunctional properties show it is much more than a biomolecular marker protein through its ability to participate in many biological processes. Further studies are warranted to fully explore the biology of this fascinating molecule, particularly in the wound repair processes. Full article

Alkali burns to the cornea cause severe damage characterized by an intense inflammatory response driven by inflammatory cytokines, which orchestrate pathological processes, including neovascularization, fibrosis, apoptosis, abnormal cell proliferation, and disorganization of the extracellular matrix (ECM), often resulting in permanent vision impairment or loss. Rapamycin (RAPA), a well-known mTOR inhibitor with potent immunosuppressive activity and pleiotropic therapeutic effects, was investigated as a novel restorative modality for promoting corneal wound healing in a mouse model of alkali burn injury. Topical RAPA treatment significantly reduced clinical signs of inflammation and decreased the infiltration of F4/80⁺ macrophages and CD45⁺ leukocytes, along with suppressed expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-17A). RAPA also markedly downregulated angiogenic mediators, such as VEGF, and endothelial markers, like CD31, resulting in significant inhibition of neovascularization. Furthermore, it prevented fibrotic tissue formation and myofibroblast activation, as evidenced by reduced α-SMA levels, and attenuated pathological matrix remodeling through decreased MMP-9 expression. Notably, RAPA preserved epithelial barrier function by maintaining the tight junction protein ZO-1 and reduced both apoptotic cell death (TUNEL) and dysregulated proliferation (Ki67⁺), thereby preserving the functional and structural integrity of the cornea. In conclusion, RAPA represents a promising therapeutic candidate for managing severe corneal alkali burn injuries, with the potential to enhance corneal wound healing, minimize long-term complications, and protect visual function. Full article

Intestinal fibrosis is a common complication of inflammatory bowel diseases (IBD), and, to date, effective and safe antifibrotic drugs are still lacking. Emerging evidence suggests that probiotics may provide novel strategies to counteract fibrotic processes. In this study, we evaluated the anti-fibrotic potential of a multi-strain probiotic formulation, OxxySlab^TM, using in vitro models of intestinal fibrosis and epithelial-to-mesenchymal transition (EMT). Human intestinal fibroblasts (CCD-18Co cell line) and epithelial cells (Caco-2 cell line, IECs) were stimulated with transforming growth factor-β1 (TGF-β1) to induce fibrotic and EMT phenotypes, respectively. Treatment with OxxySlab modulated cell proliferation and fibrosis-related markers, which we assessed through CCK-8 assay, Western blotting, and immunofluorescence. The probiotic lysate inhibited both canonical and non-canonical TGF-β1 signaling pathways, and it also reduced TGF-β1 gene expression in activated myofibroblasts, as shown by RT-qPCR. Furthermore, probiotic treatment reversed EMT features by restoring epithelial markers and downregulating mesenchymal markers. These findings highlight the beneficial effects of the multi-strain probiotic formulation as an adjunctive therapeutic agent targeting key pathways involved in intestinal fibrosis. Full article

CD44, a multi-isoform adhesion receptor for hyaluronic acid (HA), plays a crucial role in regulating cell interactions with the extracellular matrix, cell migration, differentiation, and survival in both physiological and pathological contexts. Accumulating experimental evidence suggests that CD44 is not merely a passive marker of mesenchymal cell activation but rather an active signaling hub driving fibrosis in many organs, including the lung, skin, heart, and liver. Its involvement in fibroblast differentiation into myofibroblasts, as well as induction of the invasive phenotype of these cells, shows striking analogies to the mechanisms of epithelial-to-mesenchymal transition (EMT) known from cancer progression. In this paper, we discuss both the molecular mechanisms of CD44-dependent signaling (including through EGFR, MAPK/ERK, CaMKII, lipid rafts, and Smad) and the influence of its modulation (knockout, antibodies, blockade of HA synthesis) on the course of fibrosis in in vitro and in vivo models. In addition, we present the influence of environmental pollutants—such as heavy metals, particulate matter, endocrine disruptors, and microplastics—on the activation of the HA-CD44 axis in connective tissue, with particular emphasis on their role in the induction of chronic inflammation, EMT, and extracellular matrix deposition. The collected evidence suggests that CD44 serves as a central integrator of inflammatory and fibrogenic signals, and its pharmacological modulation may represent a novel therapeutic strategy for treating fibrotic diseases and chronic inflammatory conditions. Full article

Background/Objectives: Abnormal differentiation of human skin fibroblasts into myofibroblasts contributes to fibrotic skin disorders such as hypertrophic scars, keloids, and Dupuytren’s disease. This process is characterized by increased fibroblast proliferation, enhanced differentiation into myofibroblasts, and reduced programmed cell death (apoptosis). We previously demonstrated that blue light irradiation (λ = 453 nm) significantly and dose-dependently inhibits both spontaneous and TGF-β-induced fibroblast differentiation. Methods: Because fibroblast differentiation depends on cellular energy metabolism, we investigated whether the inhibitory effect of blue light is linked to changes in the cells’ energy balance. Results: We found that blue light reduced TGF-β-induced differentiation, as shown by decreased levels of α-SMA and EDA-fibronectin, key markers of myofibroblast formation. This effect was strongly associated with almost complete inhibition of mitochondrial respiration, reduced glycolysis, a lower NAD⁺/NADH ratio, and decreased ATP production. ATP-dependent processes, including endocytosis and lysosomal activity, both essential parameters of fibroblast differentiation, were also strongly suppressed. Importantly, all these changes were fully reversible within 24 h after the last irradiation. Conclusions: Mechanistically, we propose that blue light triggers photochemical reduction in flavins in proteins of the respiratory chain and possibly the Krebs cycle, which temporarily alters cellular energy metabolism. These findings suggest that non-toxic blue light therapy (80 J/cm²) can effectively prevent factor-induced fibroblast differentiation and may serve as a standalone or supportive treatment to reduce fibrotic events such as scarring and keloid formation. Furthermore, our results indicate that targeting cellular energy metabolism, whether physically or pharmacologically, could be a promising strategy to prevent sclerotic skin disorders. Full article