Search Results (2,633)

Matrix metalloproteinases (MMPs) are a major group of proteases known to regulate the turnover of the extracellular matrix (ECM). We observed that induced MMP-12 promotes eosinophilic inflammation-related epithelial cell mesenchymal transition (EMT), bronchial fibrosis, and airway obstruction in an allergen-exposed mouse model of chronic airway diseases in allergen-exposed mice and in airway-specific CC10-IL-13-overexpressed mice. Our histological analysis showed that the parabronchial and perivascular accumulation of eosinophils, fibroblasts, and collagen is significantly decreased in MMP-12^−/− allergen-exposed mice and airway-specific rtTA-MMP-12^−/−CC-10-IL-13-overexpressed mice compared to allergen-exposed wild-type mice and rtTA-CC10-IL-13-overexpressed mice. ELISA and Western blot analyses validated these histological findings, demonstrating that EMT and profibrotic protein levels were significantly decreased in allergen-challenged MMP-12^−/− mice and rtTA-MMP-12^−/−CC10-IL-13-overexpressed mice in comparison to the allergen-exposed wild-type mice and rtTA-CC10-IL-13-overexpressed mice. In addition, we also observed that allergen-challenged MMP-12^−/− mice have improved resistance and compliance compared to allergen-challenged wild-type mice. Most importantly, we show that treatment with MMP-12 inhibitors (PF-00356231 and MMP408) restricts the induction and progression of bronchial fibrosis and airway restrictions in allergen-exposed mice and airway-specific rtTA-CC10-IL-13 mice compared to the respective control mice. Taken together, the novelty of these findings lie in the fact that induced MMP-12 regulates eosinophilic inflammation-induced bronchial fibrosis and associated airway restriction, which may be reduced by treatment with MMP-12 inhibitors. Full article

Mesenchymal stem cells (MSCs) represent a promising strategy in the field of regenerative medicine due to their multipotent differentiation capacity and immunomodulatory properties. The interaction of these cells with the extracellular matrix (ECM) and biomaterials, notably graphene oxide (GO), has proven decisive in modulating cell behavior, with the potential to optimize tissue regeneration processes. This review was conducted using the MEDLINE, Scopus, and Cochrane databases, covering studies published between 2018 and 2025, from which seven studies met the inclusion criteria, with an emphasis on in vitro and in vivo investigations regarding the association between GO and MSCs. The main findings demonstrate that GO, particularly when conjugated with polymers such as poly(L-lactic acid) (PLLA), enhances cell adhesion, stimulates proliferation, and promotes the osteogenic differentiation of MSCs, in addition to positively modulating intracellular signaling pathways. However, significant gaps remain in understanding the mechanisms and safety of GO’s therapeutic use in association with MSCs. Therefore, this review reinforces the need for further studies to deepen the characterization of the bioactive properties of GO-MSCs, aiming to enable safer and more effective clinical applications. Full article

Monocytes/macrophages promote the repair of acutely injured muscle while contributing to dystrophic changes in chronically injured muscle in Duchenne muscular dystrophy (DMD) patients and animal models including mdx and mdx^5cv mice. To elucidate the molecular mechanisms underlying this functional difference, we compared the transcriptomes of intramuscular monocytes/macrophages from wild-typed (WT) uninjured muscles, WT acutely injured muscles, and mdx^5cv dystrophic muscles, using single cell-based RNA sequencing (scRNA-seq) analysis. Our study identified multiple transcriptomically diverse monocyte/macrophage subclusters, which appear to be induced by the intramuscular microenvironment. They expressed feature genes differentially involved in muscle inflammation, regeneration, and extracellular matrix (ECM) remodeling, but none of them conform to strict M1 or M2 activation. The Gpnmb⁺Spp1⁺ macrophage subcluster, an injury-associated subcluster that features the signature genes of reported scar-associated macrophages (SAMs) involved in ECM remodeling and fibrosis, is present transiently in acutely injured muscle and persistently in chronically injured dystrophic muscle, along with the persistence of monocytes. Our findings suggest that the persistent monocyte/macrophage infiltration and activation induced by continuous injury may underlie the pathogenic roles of macrophages in mdx^5cv muscles. Controlling muscle injury and subsequent macrophage infiltration and activation may be important to the treatment of DMD. Full article

The stiffness of the extracellular matrix (ECM) plays a pivotal role in the progression of osteoarthritis (OA), particularly by promoting hypertrophic differentiation of chondrocytes, which hinders cartilage regeneration and accelerates pathological ossification. This study aimed to investigate how substrate stiffness modulates hypertrophic chondrocyte behavior and whether it can reverse their phenotype towards a more stable, chondrogenic state. A series of tunable polydimethylsiloxane (PDMS) substrates with stiffnesses ranging from 78 to 508 kPa were fabricated to simulate varying mechanical microenvironments. Hypertrophic chondrocytes were cultured on these substrates, and their morphology, nuclear architecture, gene/protein expression, and mechanotransductive signaling pathways were systematically evaluated. After 7 to 21 days of culture, the chondrocytes on stiffer matrices exhibited enlarged nuclei, increased cytoskeletal tension, and enhanced focal adhesion signaling. This corresponded with the upregulation of osteogenic and hypertrophic markers such as RUNX2, COL10A1, and COL1A1. In contrast, cells on softer substrates (78 kPa) displayed reduced nuclear YAP localization, higher levels of phosphorylated YAP, and significantly increased expression of COL2A1 and SOX9, indicating reversion to a chondrogenic phenotype. Furthermore, differential activation of Smad1/5/8 and Smad2/3 pathways was observed depending on matrix stiffness, contributing to the phenotype shift. Matrix stiffness exerts a significant regulatory effect on hypertrophic chondrocytes via YAP-mediated mechanotransduction. Soft substrates promote phenotype reversion and cartilage-specific gene expression, offering a promising biomechanical strategy for cartilage tissue engineering and OA intervention. Full article

Facial aging is a multifactorial process involving changes in bone, fat compartments, ligaments, muscles, and skin. Collagen biostimulators, including synthetic agents and autologous platelet concentrates, have gained attention for facial rejuvenation. Injectable platelet-rich fibrin (i-PRF), a second-generation autologous concentrate, has shown promising regenerative properties due to its natural composition and growth factors. Cosmetic peptides, such as palmitoyl pentapeptide-4 (Matrixyl) and Tetrapeptide-21 (GEKG), are also studied for their ability to stimulate collagen synthesis and remodel the extracellular matrix. This in vitro study examined the potential synergistic effects of i-PRF combined with Matrixyl or GEKG on human dermal fibroblast viability, proliferation, and ECM-related gene expression. Fibroblasts were cultured under six conditions: control, i-PRF alone, Matrixyl alone, GEKG alone, i-PRF + Matrixyl, and i-PRF + GEKG. Viability and proliferation were assessed via MTT, crystal violet, and RealTime-Glo™ assays. Gene expression of COL1A1, FN1, and HAS1 was measured using RT-qPCR. The combinations, especially i-PRF + GEKG, led to increased cell viability and upregulated ECM-related genes at 72 h. These effects were stronger than the individual treatments, suggesting synergistic effects, especially with GEKG. These findings highlight the clinical potential of combining autologous platelet concentrates with bioactive peptides for dermal regeneration. Further preclinical and clinical studies are warranted. Full article

Osteochondral regeneration remains a major clinical challenge due to the complex architecture and biomechanical demands of the osteochondral unit. Bioactive hydrogels have emerged as promising materials capable of supporting repair through their capacity to mimic the extracellular matrix (ECM), enable cell encapsulation, and deliver bioactive cues. However, recent insights reveal that simply engineering hydrogels for structural and cellular support is insufficient. A new paradigm is emerging—one that embraces the complexity of the osteochondral niche by integrating immunomodulatory and mechanobiological cues into biomaterial design. In particular, the hydrogel’s capacity to modulate macrophage polarization and support the immunoregulatory function of mesenchymal stem cells (MSCs) is critical to orchestrate regenerative outcomes. Simultaneously, the mechanical properties of hydrogels—such as stiffness, porosity, and viscoelasticity—can profoundly influence stem cell fate and local tissue morphogenesis. This review discusses recent advances in hydrogel-based strategies for osteochondral repair, highlighting the interplay between immunological signals and the mechanical microenvironment, and calls for a shift from reductionist tissue-engineering approaches to systems-level design of tunable, immuno-mechanobiological microenvironments. Full article

Almost every cell of a multicellular organism is in contact with the extracellular matrix (ECM), which provides the shape and mechanic stability of tissue, organs and the entire body. At the molecular level, cells contact the ECM via integrins. Integrins are transmembrane cell adhesion molecules that connect the ECM to the cytoskeleton, which they bind with their extracellular and intracellular domains. Cysteine residues are abundant in both integrin subunits α and β. If pairwise oxidized into disulfide bridges, they stabilize the folding and molecular structure of the integrin. However, despite the oxidative environment of the extracellular space, not all pairs of cysteines in the extracellular integrin domains are permanently engaged in disulfide bridges. Rather, the reversible and temporary linkage of cystine bridges of these cysteine pairs by oxidation or their reductive cleavage can cause major conformational changes within the integrin, thereby changing ligand binding affinity and altering cellular functions such as adhesion and migration. During recent years, several oxidoreductases and thiol isomerases have been characterized which target such allosteric disulfide bridges. This outlines much better, albeit not comprehensively, the role that such thiol switches play in the redox regulation of integrins. The platelet integrin αIIbβ3 is the best examined example so far. Mostly referring to this integrin, this review will provide insights into the thiol switch-based redox regulation of integrins and the known effects of their allosteric disulfide bridges on conformational changes and cell functions, as well as on the machinery of redox-modifying enzymes that contribute to the redox regulation of cell contacts with the ECM. Full article

The tumor microenvironment (TME) has a substantial impact on the progression of gastric cancer. Collagen, the most abundant protein in the extracellular matrix (ECM), forms a dense physical barrier that regulates anti-tumor immunity in the TME. It is a significant regulator of the signaling pathways of cancer cells, which are responsible for migration, proliferation, and metabolism. ECM proteins, particularly remodeling enzymes and collagens, can be modified to increase stiffness and alter the mechanical properties of the stroma. This, in turn, increases the invasive potential of tumor cells and resistance to immunotherapy. Given the dynamic nature of collagen, novel therapeutic strategies have emerged that target both collagen biosynthesis and degradation, processes that are essential for addressing ECM stiffening. This review delineates the upregulation of the expression and deposition of collagen, as well as the biological functions, assembly, and reorganization that contribute to the dissemination of this aggressive malignancy. Furthermore, the review emphasizes the importance of creating 3D in vitro models that incorporate innovative biomaterials that avoid the difficulties of traditional 2D culture in accurately simulating real-world conditions that effectively replicate the distinctive collagen microenvironment. Ultimately, it investigates the use of decellularized ECM-derived biomaterials as tumor models that are designed to precisely replicate the mechanisms associated with the progression of stomach cancer. Full article

The Tumour Microenvironment (TME) is pivotal for melanoma progression and contributes to therapy resistance. While dermal cell involvement is well established, the role of epidermal cells remains less defined. To explore the contribution of Normal Human Keratinocytes (NHKs) to melanoma biology, we investigated the modification of gene and protein expression of NHKs exposed to melanoma-conditioned medium or maintained in a co-culture system. The analysis focused on pathways related to proliferation, inflammation, Extracellular Matrix (ECM) remodelling, and cell adhesion. Due to the well-documented melanoma–fibroblast crosstalk, Normal Human Fibroblasts (NHFs) and Cancer-Associated Fibroblasts (CAFs) were used as comparative references. Keratinocyte gene expression changes under the influence of melanoma secretome only partially overlapped with those of NHFs and CAFs, indicating cell-type-specific responses. Exposure to melanoma-conditioned medium induced the upregulation of bFGF, CXCL-16, TIMP-2, and E-cadherin in NHKs, alongside downregulating TGF-β and MMP-9. Although bFGF is a recognized pro-tumorigenic factor, the modulation of CXCL-16, TIMP-2, and TGF-β may reflect a protective response. Notably, under co-culture conditions, NHKs exhibited a pronounced pro-inflammatory and ECM-remodelling phenotype, characterized by elevated production of cytokines (IL-1α, IL-1β, and IL-8) and ECM-degrading enzymes (MMP-7, 9, 12, and 13), indicative of a pro-tumoral feature. Collectively, these findings underscore an active role for NHKs in melanoma initiation and progression. Full article

Osteoarthritis (OA) is a multifactorial joint disease traditionally characterized by cartilage degradation, while growing evidence underscores the critical role of synovial fibrosis in driving disease progression. The synovium exhibits pathological remodeling in OA, primarily due to the phenotypic transition of fibroblast-like synoviocytes (FLSs) into myofibroblasts. This fibroblast–myofibroblast transition (FMT) results in excessive deposition of extracellular matrix (ECM) and increased tissue stiffness and contractility, collectively contributing to chronic inflammation and fibrotic stiffening of the joint capsule. These fibrotic changes not only impair synovial function but also exacerbate cartilage degeneration, nociceptive sensitization, and joint dysfunction, thereby amplifying OA severity. Focusing on the frequently overlooked role of the FMT of synovial fibroblasts in OA, this review introduces the biological characteristics of FLSs and myofibroblasts and systematically examines the key molecular pathways implicated in OA-related FMT, including TGF-β, Wnt/β-catenin, YAP/TAZ, and inflammatory signaling cascades. It also discusses emerging therapeutic strategies targeting synovial fibrosis and FMT and considers their implications for the clinical management of OA. By highlighting recent advances and unresolved challenges, this review provides critical insights into the fibroblast–myofibroblast axis as a central contributor to OA progression and a promising therapeutic target for modifying disease trajectory. Full article

Background and Objectives: Osteoarthritis (OA) is a degenerative joint disease involving inflammation, oxidative stress, and extracellular matrix (ECM) degradation, leading to cartilage damage and joint dysfunction. This study aimed to evaluate the chondroprotective effects of intra-articular hydrolyzed collagen in a rat model of knee OA using a dual-compartment biochemical and histological approach. Materials and Methods: Twenty male Sprague-Dawley rats underwent ACL transection to induce osteoarthritis and were randomly assigned to receive intra-articular hydrolyzed collagen or saline once weekly for three weeks. At six weeks, knee joints were evaluated histologically using the Mankin score. Synovial fluid and cartilage homogenates were analyzed via enzyme-linked immunosorbent assay (ELISA) for cytokines, cartilage degradation markers, and oxidative stress indicators. Results: The collagen-treated group demonstrated significantly lower Mankin scores. Levels of pro-inflammatory cytokines, interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), as well as cartilage degradation markers, matrix metalloproteinase-13 (MMP-13), C-terminal crosslinked telopeptide of type II collagen (CTX-II), and cartilage oligomeric matrix protein (COMP), were significantly reduced (p < 0.05). Additionally, oxidative stress indicators including inducible nitric oxide synthase (iNOS), total oxidant status (TOS), and oxidative stress index (OSI) were decreased, while total antioxidant status (TAS) was increased in both synovial fluid and cartilage homogenates (p < 0.05). Conclusions: Intra-articular hydrolyzed collagen reduced inflammation, oxidative stress, and extracellular matrix (ECM) degradation, indicating potential chondroprotective effects across both synovial and cartilage compartments. Full article

Autophagy is a crucial cellular process responsible for sustaining homeostasis through the degradation and recycling of proteins and organelles, providing energy during amino acid starvation and hypoxia. In cancer, autophagy can either inhibit tumor growth or support cancer cell survival. Our previous studies have shown that re-expression of the tumor suppressor gene DIRAS3 inhibits growth of ovarian cancer cells, promotes autophagic cell death in vitro, and induces tumor dormancy in vivo. Growth factors and extracellular matrix (ECM) components can, however, inhibit DIRAS3-induced autophagic cell death. This study explores whether fibronectin (FN) can counteract the growth inhibition induced by DIRAS3 in ovarian cancer cells. FN was found to inhibit DIRAS3-induced autophagy and to partially rescue ovarian cancer cells from DIRAS3-induced cell death while reducing DIRAS3-induced inhibition of p-FAK and p-AKT. Inhibiting FAK with defactinib in ovarian cancer cells enhanced DIRAS3-induced autophagy and cell death. Re-expression of DIRAS3 and treatment with defactinib produced tumor regression in xenograft models. Our findings suggest that ECM components in the tumor microenvironment like FN enhance the activities of β1 integrin, FAK, and AKT to inhibit DIRAS3-induced autophagic cell death, thereby promoting ovarian cancer cell survival. Full article

Obesity is one of the most challenging metabolic disorders affecting more than 800 million people around the world, according to the World Health Organization (WHO). In recent years, our knowledge and understanding of this multifactorial disease have been exponentially increasing, and many studies have been focusing on one of the main organs affected by obesity: adipose tissue (AT). It is known that AT undergoes remodeling due to the abnormal fat accumulation that accompanies obesity, characterized by increased immune cell infiltration, extracellular matrix (ECM) overproduction, and decreased adipogenesis, among others. Few studies have focused on adipocyte intercommunication, even though it is essential for AT homeostasis and function. In this context, GAP junction, adherens junction, and tight junction proteins can be found in these depots. In some cases, their function is well established, but in most cases it remains unknown. Claudins are the main proteins that form tight junctions (TJs), and, in recent years, studies have revealed a more extensive role of claudin proteins in intracellular signaling and control of a wide set of biological processes. This review aims to gather the main scientific evidence on the role of claudins in cell signaling, as well as what is known about these proteins in the field of obesity and adipose tissue physiology. Full article

Background: Esophageal cancer (EC), including esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), remains a lethal malignancy with limited molecularly tailored treatment options. Due to substantial histologic and transcriptomic differences between subtypes, therapeutic responses often vary, underscoring the need for subtype-stratified analysis and precision drug discovery. Methods: We integrated transcriptomic data from GEO and TCGA to identify differentially expressed genes (DEGs) specific to EAC, ESCC, and their shared profiles. Functional enrichment (GO, KEGG) and protein–protein interaction (PPI) network analyses were conducted to extract hub genes using DAVID, STRING, and Cytoscape. Survival associations were evaluated using TCGA-ESCA and UALCAN. Drug repurposing was performed using L1000FWD, L1000CDS2, and SigCom LINCS. Results: We identified 79, 59, and 17 hub genes in the DEG-EAC, DEG-ESCC, and DEG-EAC&ESCC datasets, respectively. In EAC, 16 novel hub genes including SCARB1, SERPINH1, and DSC2 were discovered, which had not been previously implicated in this subtype. These genes were significantly enriched in pathways related to extracellular matrix (ECM) remodeling and epithelial structure. In addition, shared hub genes across EAC and ESCC—such as COL1A1, SPARC, and MMP1—were enriched in ECM organization and cell adhesion processes, highlighting convergent tumor–stroma interactions. Drug repositioning analysis consistently prioritized MEK inhibitors, trametinib and selumetinib, as potential therapeutic candidates across all DEG datasets. Conclusions: This study presents a comprehensive, subtype-stratified transcriptomic framework for EC, identifying both unique and shared hub genes with potential functional relevance to ECM dynamics. Our findings suggest that ECM remodelers may serve as therapeutic targets, and highlight MEK inhibition as a promising, yet exploratory, repurposing strategy. While these results offer a molecular foundation for future precision oncology efforts in EC, further validation through proteomic analysis, functional studies, and clinical evaluation is warranted. Full article

With the growing interest in natural strategies for preventing skin aging, plant-derived compounds are being actively investigated for their potential protective effects against skin inflammation and extracellular matrix (ECM) degradation. In this study, we explored the anti-aging and anti-inflammatory effects of harringtonine, an alkaloid isolated from Cephalotaxus harringtonia, in normal human epidermal keratinocytes (NHEKs) under inflammatory stress induced by tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ). Harringtonine significantly suppressed the expression of matrix metalloproteinases (MMP)-1, MMP-2, and MMP-9 and restored the expression of collagen synthesis-related genes [collagen type I alpha 1 chain (COL1A1), collagen type I alpha 2 chain (COL1A2), and collagen type IV alpha 1 chain COL4A1)], indicating its protective role in ECM degradation. Additionally, harringtonine improved the expression of skin barrier-related genes, such as serine peptidase inhibitor kazal type 5 (SPINK5), loricrin (LOR), quaporin-3 (AQP3), filaggrin (FLG), and keratin 1 (KRT1) although it had no significant effect on involucrin (IVL). Harringtonine also markedly reduced the production of pro-inflammatory cytokines [interleukin (IL)-1β, IL-6, and IL-8] and inflammatory mediators, including prostaglandin E₂ (PGE₂), cyclooxygenase-2 (COX-2), and nitric oxide (NO). Our findings suggest that harringtonine may serve as a promising natural compound for mitigating skin aging and inflammation through multi-targeted modulation of ECM remodeling, skin barrier function, and inflammatory response. Full article