Search Results (261)

The small heat shock protein HSPB1 is a ubiquitously expressed mechanoresponsive chaperone essential for cytoskeletal remodeling under mechanical load. Mutations in HSPB1, including S135F, cause Charcot-Marie-Tooth (CMT) peripheral neuropathy, yet the mechanisms underlying the selective vulnerability of peripheral nerves remain enigmatic. Here we demonstrate that substrate stiffness is a critical determinant of HSPB1^S135F-mediated neurodegeneration. Using stiffness-tunable polydimethylsiloxane (PDMS) substrates (1 kPa, 10 kPa, 2 MPa) and uniaxial cyclic stretch, we show that primary dorsal root ganglia (DRG) neurons and SH-SY5Y cells expressing HSPB1^S135F exhibit profound deficits in mechanoadaptation. On compliant substrates (10 kPa), HSPB1^S135F causes stretch-induced axon fragmentation and neuronal death, whereas HSPB1^WT confers robust neuroprotection. HSPB1^S135F also disrupts stiffness-directed neuritogenesis in differentiated SH-SY5Y cells: HSPB1^WT-expressing cells show optimal axonal outgrowth and βIII-tubulin expression on 10 kPa substrates mimicking muscle tissue stiffness, while HSPB1^S135F mutants display disorganized focal adhesions and complete differentiation failure. Mechanistically, we uncover that HSPB1^S135F dysregulates stage-specific transglutaminase (TGase) expression—insufficient TGase during early neuritogenesis impairs filopodia stabilization, whereas aberrant TGase persistence at late stages constrains axon extension. Our findings establish HSPB1 as a biomechanical sensor that integrates ECM stiffness signals to coordinate peripheral nerve regeneration, and identify defective mechanoadaptation as a previously unrecognized pathomechanism in CMT. These results open new avenues for stiffness-targeted therapeutic strategies in peripheral neuropathy. Full article

Craniosynostosis is a congenital bone developmental condition characterized by the premature ossification of calvarial sutures, leading to restricted skull expansion and potential neurological complications. Although little is known about the signaling that governs this accelerated fusion, our research group has previously identified a stiffness-dependent upregulation of osteogenic genes in cells derived from fused sutures, highlighting the role of mechanotransduction in disease progression. Building on these findings, the present study describes the development of a unique patient-derived three-dimensional (3D) tissue-engineering (TE) model of non-syndromic craniosynostosis (NS-CS) to investigate how extracellular matrix (ECM) composition and biochemical cues regulate ossification timing and patterns. Cells isolated from clinically relevant tissues, surgically obtained from patent and prematurely fused calvarial sutures of pediatric NS-CS patients, were characterized and cultured under both two-dimensional (2D) and 3D suture-mimicking conditions. Comparative analysis revealed differences in cellular responsiveness between cells isolated from fused and patent sutures across the different experimental conditions, with cells from fused sutures consistently exhibiting higher expression of osteogenic markers. Notably, the elevated expression of osteogenic and chondrogenic markers suggested the possible involvement of endochondral-like ossification mechanisms during the pathological process of suture fusion. This patient-derived model was designed to recapitulate biophysical and biochemical features of the extracellular matrix of healthy and pathological sutures, serving as a tool for future research, helping us to understand the underlying mechanisms behind the pathophysiology of craniosynostosis. Full article

Acute or chronic rotator cuff tears are major causes of shoulder dysfunction, motivating the development of scaffolds with tailored thickness and mechanics for supraspinatus tendon regeneration. This study aimed to investigate the effect of bilayer poly(butylene adipate-co-terephthalate) (PBAT) scaffold thickness on the tenogenic differentiation of rat adipose mesenchymal stem cells (r-AdMSCs) and supraspinatus tendon regeneration. Aligned fibers with a diameter of approximately 476 nm were deposited onto randomly oriented layers at different times (4 h; 4S, 6 h; 6S, 8 h; 8S), and scaffolds with increasing thicknesses from 441 µm (4S) to 1132 µm (8S) were produced. Mechanical testing showed comparable tensile strength for 4S and 6S (≈1.9–2.0 MPa) and modulus (5.5–7.3 MPa), while 8S exhibited markedly reduced stiffness (0.5 MPa) and hyper elastic deformation. Mechanical performance across degradation conditions remained strongly thickness-dependent: thinner scaffolds retained integrity and strengthened, with modulus increases during hydrolytic and enzymatic degradation, whereas thicker matrices showed limited remodeling and instability. Rat-AdMSCs’ were cultured on the scaffolds for 21 days. Cell-free and cell-laden mechanical responses further reflected thickness effects: cell-free samples stiffened due to media-induced passive matrix tightening, whereas cell-laden scaffolds showed extracellular matrix (ECM)-driven reinforcement, most prominently in 4S, which reached 2.1 MPa tensile strength with improved elasticity and balanced deformation. The 4S scaffold exhibited the highest tensile strength and significantly increased collagen-1 (col1), tenomodulin (tnmd) and scleraxis (scx) expression compared with the other groups. In conclusion, among all groups, 4S scaffolds demonstrated the most favorable mechanical and biological performance, suggesting that scaffold thickness plays a critical role in regulating tendon regeneration and will become even more suitable when matured in bioreactors. Full article

Plexiform neurofibromas (pNF1s) are benign peripheral nerve sheath tumors caused by NF1 loss, leading to dysregulated RAS/mitogen-activated protein kinase (MAPK) signaling. While the mitogen-activated protein kinase kinase (MEK) inhibitors, selumetinib and mirdametinib, can reduce tumor volume, surgical resection remains the primary treatment for immediate debulking and symptom relief. Complete removal is often limited by tumor infiltration along nerve plexuses, and residual tumors may undergo postsurgical tissue remodeling, producing localized regions of stiffened extracellular matrix (ECM). The impact of ECM stiffness on pNF1 growth and drug responses remains unclear. Using immortalized patient-derived pNF1 tumor cell lines cultured in 3D hydrogels with defined stiffness (1.5 kPa, soft; 7 kPa, stiff), we found that stiff ECM promoted spread morphology, increased growth, and progressive intracellular softening. Stiff ECM also reduced lysyl oxidase (LOX) expression, suggesting mechanoadaptive ECM remodeling, and increased P-glycoprotein expression. Under the same conditions, stiff ECM was associated with reduced sensitivity to selumetinib. These results provide the first evidence that ECM stiffening, including that plausibly associated with postsurgical remodeling, may contribute to pNF1 growth and reduced sensitivity to selumetinib in this 3D pNF1 culture model. Our findings highlight mechanobiology as a key regulator of tumor behavior and support further investigation of ECM-targeted strategies to improve outcomes in neurofibromatosis type 1 (NF1). Full article

Glioblastomas (GB) are highly aggressive brain tumors with poor patient prognosis and low survival rates. To identify novel therapeutic targets, the tumor microenvironment (TME) is increasingly examined, with a particular focus on biomechanical changes in the extracellular matrix (ECM) that contribute to GB aggressiveness. In GB, the ECM stiffens, regulating cell behavior through mechanotransduction. Preclinical in vitro and ex vivo studies generally report increased stiffness in GB relative to healthy brain tissue, whereas clinical in vivo measurements often report decreased stiffness. This review examines potential causes for this discrepancy, highlighting both biological and technical factors. Preclinical measurements are frequently performed using atomic force microscopy (AFM), while clinical stiffness is assessed via magnetic resonance elastography (MRE). Differences in methodology, including sample preparation, measurement modalities, and spatial scale, partly explain divergent stiffness values. Biological factors such as necrosis, edema, and physical confinement by the skull, which are preserved only in vivo, also contribute to these differences. To reconcile these findings, future research should employ physiologically relevant in vitro models that better replicate in vivo GB biomechanics, together with high-throughput and accurate animal models. Integrating these approaches may clarify the biomechanical landscape of GB and result in more effective therapeutic strategies. Full article

Exosomal microRNAs (miRNAs) are key mediators of intercellular communication in the breast cancer tumor microenvironment (TME), facilitating bidirectional signaling between malignant cells and the desmoplastic stroma. This review explores current evidence on their dual roles as drivers of stromal remodeling and as circulating biomarkers of therapeutic resistance across major breast cancer subtypes, including triple-negative breast cancer (TNBC), hormone receptor-positive (ER+/PR+) disease, and HER2-amplified tumors. We outline how miR-9, miR-21, and miR-181 family members promote cancer-associated fibroblast (CAF) activation, increase extracellular matrix (ECM) stiffness, and sustain a reverse Warburg phenotype. We then detail subtype-specific resistance mechanisms: miR-181 family members suppress BCLAF1 to block doxorubicin-induced apoptosis; miR-221/222 downregulates ESR1 and p27Kip1 to confer tamoxifen resistance; miR-155 impairs homologous recombination in TNBC; and miR-1246 sustains PI3K/AKT signaling in HER2-positive disease. We also evaluate circulating exosomal miRNA panels as liquid biopsy tools for predicting chemotherapy response and tracking resistance emergence. Finally, we discuss therapeutic strategies including antagomirs, miRNA replacement therapy and engineered exosome platforms, and address key challenges such as assay standardization and regulatory hurdles, that must be overcome for clinical translation. Full article

The cardiac extracellular matrix (ECM) is a dynamic, mechanically active network continuously shaped and interpreted by cardiomyocytes, fibroblasts, and macrophages. Interdependent mechanosensing, force transmission, and ECM remodeling functions create multicellular feedback loops that control tissue stiffness, alignment, maturation, and fibrotic remodeling. Together, these biomechanical processes create reciprocal signaling pathways in which cellular behavior modifies the ECM while the ECM’s mechanics concurrently shape cellular phenotype and function. This review explores cell–ECM mechanoreciprocity, a physiologic framework that unifies cell-sensing mechanotransduction, mechano-electrical coupling, and ECM-based biochemical signaling with cell-driven ECM remodeling. We propose three interconnected feedback loops that integrate biochemical and mechanical cues across cell types: load amplification, structural alignment, and immune regulation. We discuss how advanced two- and three-dimensional engineered cardiac systems incorporating tunable and dynamic mechanical cues can be used to model these interactions. We address the limitations of existing experimental platforms and the need for better models to fully recapitulate in vivo complexities. Understanding and recreating these reciprocal mechanical interactions will provide essential frameworks for disease modeling and therapeutic development while reducing reliance on in vivo studies. Full article

This is a narrative conceptual paper, not a systematic review. Ultrasound-guided fascial hydrorelease (FHR) has been reported to provide sustained pain relief in patients with chronic musculoskeletal pain; however, its underlying biological mechanisms remain incompletely understood. In this paper, we propose the “Fascial Memory Reset Hypothesis” as an integrative framework linking mechanobiology, extracellular matrix (ECM) remodeling, peripheral nociception, microcirculatory dynamics, and ultrasound imaging findings. Mechanobiological research has demonstrated that increased tissue stiffness activates YAP/TAZ signaling, promoting fibroblast activation, ECM deposition, and mechano-epigenetic regulation. These mechanically driven processes can stabilize pathological tissue phenotypes without DNA sequence alterations. The “Fascial Memory Reset Hypothesis” proposes that targeted mechanical interventions such as FHR may partially reverse these mechanically maintained states by restoring tissue mobility and modifying stiffness-dependent mechanotransduction. We propose that “stacking fascia” (observed as layered hyperechoic bands on ultrasound) represents the macroscopic structural phenotype of mechano-epigenetic memory formed through sustained mechanical stress. Integrating molecular mechanotransduction pathways, mechano-epigenetic mechanisms, neural sensitization, and vascular factors, we propose that FHR may hypothetically partially normalize pathological fascial states by mechanically restoring tissue mobility and modifying stiffness-dependent signaling. Although direct molecular evidence of the effect of FHR in human fascia remains limited, this hypothesis provides a biologically plausible link between mechanical stress, ultrasound-visible structural alterations, and sustained clinical improvement. Full article

Background and Objectives: Cutaneous melanoma (CM) is one of the most aggressive skin malignancies due to its rapid progression and high therapeutic resistance. Growing evidence demonstrates that the tumor microenvironment (TME)—comprising diverse immune, stromal, vascular, and epidermal cell populations alongside various cytokines and growth factors, as well as extracellular matrix (ECM) components—plays a crucial role in tumor heterogeneity, metastatic potential, and response to therapy. This review aims to synthesise current knowledge on the cellular and non-cellular constituents of the CM microenvironment and clarify their contributions to tumor progression, immune evasion, and treatment resistance. Materials and Methods: We conducted a narrative review of recent experimental, clinical, and translational studies investigating melanoma–microenvironment interactions, integrating evidence from in vitro, in vivo, and human tissue analyses. Results: Melanoma exhibits marked intra-tumoral heterogeneity driven by genetic, epigenetic, and microenvironmental influences. Cancer-associated fibroblasts, adipocytes, endothelial cells, and keratinocytes are reprogrammed by melanoma cells to promote invasion, angiogenesis, and metastasis. Immune subsets play divergent roles: neutrophils, M2 macrophages, myeloid-derived suppressor cells, and tolerogenic dendritic cells foster immune suppression, while lymphocytes—particularly CD8⁺ T cells, TFH cells, and B cells —are associated with improved outcomes but often become dysfunctional. ECM remodeling, including collagen deposition, integrin signaling, and increased matrix stiffness, actively remodels the tissue to support tumor growth and immune evasion. Hypoxia-inducible factor (HIF)-mediated signaling drives cell dedifferentiation, angiogenesis, and metabolic changes that contribute to treatment resistance. Consequently, emerging therapeutic strategies are moving beyond targeting tumor cells alone to focus on modulating TME components, counteracting immunosuppression, hypoxia, metabolic reprogramming, and extracellular vesicle signaling. Conclusions: The TME profoundly modulates tumor behavior and therapeutic response. A deeper understanding of the reciprocal interactions between melanoma cells and their microenvironmental components may enable the development of more effective strategies for early detection, prognosis, and personalized therapies. Full article

High-frequency proton therapy shows promise for breast cancer (BC) treatment. We previously showed that BC cells’ metastatic potential (MP) correlates with their nanoparticle (NP) uptake efficiency. MP is known to be associated with microenvironment stiffness and radiosensitivity. Here, proton beam-irradiated MCF-7 and MDA-MB-231 cells were assessed for NP uptake efficiency under stiff (plastic) or soft (fibrin gel) conditions. In a stiff microenvironment, control MDA-MB-231 cells internalized 1.35-fold more NPs than MCF-7 (p < 0.0017), with comparably low uptake in soft conditions. After proton beam irradiation at a dose of 6 Gy, in stiff conditions, MDA-MB-231 cells showed a 1.6-fold increase in NP internalization compared to non-treated MDA-MB-231 (p < 0.0001), while MCF-7 cells showed no change, leading to an overall 1.86-fold difference between proton-treated MDA-MB-231 and MCF-7 cells (p < 0.0001). In soft conditions, irradiated MDA-MB-231 retained a 1.47-fold higher uptake of NPs than MCF-7 cells (p < 0.0172), but this value was 1.7-fold lower (p < 0.0001) compared to non-irradiated MDA-MB-231 cells on stiff plastic. Hence, therapeutic strategies combining proton irradiation with targeting tumor microenvironment softening may reduce post-irradiation metastasis risk. Full article

Human induced pluripotent stem cell (iPSC)-derived brain organoids have emerged as powerful three-dimensional (3D) platforms for modeling human neurodevelopment and neurological disorders. However, the absence of a functional vascular network remains a critical limitation, restricting oxygen and nutrient delivery, impairing metabolic stability, and constraining long-term maturation. Conventional extracellular matrix (ECM) mimetics, such as Matrigel and other static synthetic hydrogels, provide biochemical support but fail to recapitulate the dynamic remodeling that characterizes the developing neurovascular niche. Recent advances in stimuli-responsive hydrogels offer spatiotemporal control over matrix stiffness, degradability, viscoelasticity, and biochemical cue presentation. In this review, we discuss dynamic hydrogel systems within a structure–property–function framework, highlighting how network chemistry and architecture may regulate endothelial sprouting, lumen formation, vascular stabilization, and neurovascular unit maturation in vascularized brain organoid models, based on evidence from both organoid studies and related biomaterial or vascular systems. Photoresponsive, enzyme-cleavable, thermo-responsive, supramolecular, bio-orthogonal click-based, and bioprinted platforms are discussed with emphasis on mechanotransduction, angiocrine signaling, and barrier specialization. Functional outcomes, including trans-endothelial electrical resistance, selective permeability, transporter expression, electrophysiological integration, and sustained perfusion, are discussed alongside translational challenges such as cytocompatibility, oxidative stress, scalability, and regulatory feasibility. Collectively, dynamic hydrogels provide a versatile biomaterial strategy for improving vascularization and aspects of functional maturation in brain organoid models with enhanced physiological relevance. Ultimately, stimuli-responsive hydrogel systems may serve as enabling platforms for engineering vascularized brain organoids and advancing human-relevant neurovascular disease modeling. Full article

Nuclear mechanics and mechanotransduction are involved in the migration and invasion process, such as those in which the cells need to deform themselves to pass through constrictions. Specifically, properties like nuclear softness, viscoelasticity, plasticity (like nuclear pore complexes) and deformability are critical in cancer and its malignant progression. The nucleus represents a physical barrier for the migration and invasion in dense 3D extracellular matrix (ECM) scaffolds. Therefore, the deformability of the nucleus seems to determine the migration limit in circumstances where the enzymatic remodeling of the surroundings is impaired. There are still significant knowledge gaps regarding effects of nuclear deformation during cancer dissemination. It seems that nuclear deformation can alter gene transcription, induce alternative splicing processes, impact nuclear envelope rupture, nuclear pore complex dilatation, damage the DNA, and increase the genomic instability. These mechanically induced alterations can in turn impact the migratory behavior of the cancer cells. The stiffness of the nucleus relies on the condensation of chromatin, and the nuclear lamina, which consists of a network of intermediate filaments underneath the nuclear envelope. All of this is discussed in the review and it is argued that nuclear deformability is universally found in various cancer types. Another focus is placed on the nuclear envelope proteins like emerin, and the SUN-KASH complex and how they contribute to the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, which consequently couples the nucleus and the cytoskeleton. It is argued that this connection is crucial for force transmission, which governs nuclear stiffness dynamically, depending on the force applied. In this review, recent findings are described that couple ECM-induced nuclear mechanosensing and mechanotransduction with the migration and invasion of cancer cells. Moreover, it is suspected that changes in the mechanosensory characteristics of the cell nucleus could play a pivotal part in the malignancy of cancer cells and the heterogeneity of tumors. Finally, it is discussed what impact the individual elements of the nucleus offer to mechanically alter cellular migration and invasion in cancer and its malignant progression. Full article

Mesenchymal stem cells (MSCs) sense biophysical cues from their microenvironment, which regulate cytoskeletal organization and the nuclear–cytoplasmic distribution of the mechanotransducer Yes-associated protein (YAP), thereby shaping cellular behavior. Prolonged ex vivo culture on non-physiologically rigid substrates induces persistent nuclear YAP localization, a phenomenon often referred to as mechanical memory. We therefore examined whether transient epigenetic modulation could modulate YAP subcellular localization in human bone marrow-derived MSCs. Treatment with the DNA methyltransferase inhibitor 5-azacitidine (5-Aza) shifted YAP localization toward the cytoplasm in MSCs, without overt changes in pluripotency marker expression or neural differentiation capacity. RNA sequencing revealed broad down-regulation of extracellular matrix (ECM)-related genes following 5-Aza treatment. Independent suppression of ECM production via TGF-β signaling similarly promoted cytoplasmic YAP localization. When subsequently transferred to soft substrates, 5-Aza–treated MSCs restored YAP relocalization despite prior expansion on stiff surfaces. Together, these findings suggest that transient 5-Aza treatment can partially alleviate mechanically induced YAP regulation associated with mechanical memory. Thus, simple and transient administration of 5-Aza may offer a practical means to improve the quality of MSCs during ex vivo expansion for cell-based therapies. Full article

Cardiac fibrosis represents a final common pathway in a wide range of cardiac disorders, leading to structural remodeling, diastolic dysfunction, and heart failure. From a pathologist’s viewpoint, fibrotic remodeling displays distinctive morphologic patterns such as interstitial, perivascular, and replacement fibrosis, which mirror specific cellular and molecular mechanisms. Central to this process is the activation of cardiac fibroblasts into myofibroblasts, driven by profibrotic signaling cascades such as transforming growth factor beta (TGF-β)/mothers against decapentaplegic homolog proteins (SMAD), Wingless/Integrated signaling pathway (Wnt)/βeta-catenin, and Hippo-Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) pathways. Neurohumoral mediators, including angiotensin II and aldosterone, further amplify extracellular matrix synthesis and tissue stiffness. Epigenetic modulators and non-coding RNAs (n-c RNAs) orchestrate transcriptional programs that perpetuate fibroblast activation. Histopathological correlates of these molecular events, collagen deposition, alpha-smooth muscle actin (α-SMA) expression, and extracellular matrix (ECM) cross-linking, can be demonstrated through immunohistochemistry and digital morphometry. This review integrates molecular signaling and morphologic evidence to delineate the mechanisms of cardiac fibrosis, emphasizing the pathologist’s role as a link between molecular insight and diagnostic interpretation. Understanding these intertwined processes provides the foundation for novel antifibrotic therapies targeting key molecular nodes of fibroblast activation and matrix remodeling. Full article

Background/Objectives: Hepatocellular carcinoma (HCC) is the sixth most prevalent cancer and a chief cause of cancer-related mortality throughout the world. SIRT6 is a fundamental sirtuin that governs several disease processes encompassing inflammation and cancer, including HCC. Longevity in centenarian Ashkenazi Jews was recently associated to novel allelic variants of SIRT6 (N308K/A313S), which ameliorate genome maintenance and DNA repair, and suppress cancer cells. It is currently unknown whether the above-mentioned SIRT6 variants display divergent or similar roles in HCC pathogenesis, compared to the wild-type (WT) counterpart. Methods: Our goal was to elucidate how these new centenarian-associated SIRT6 genetic variants may modulate HCC cell lines’ (HepG2 and Huh-7) aggressiveness and behavior, using functional and transcriptomic approaches. Results: We demonstrate that adeno-associated virus (AAV2/8)-mediated overexpression of centenarian-associated SIRT6 variants hampered HCC cell proliferation, with transcriptomic data showing the modulation of hallmark genes involved in the turnover of collagen/extracellular matrix (ECM). In addition, we found that AAV2/8-mediated overexpression of SIRT6 N308K/A313S decreased invasion and also increased stiffness in HCC cells, as measured by nanoindentation, in a more pronounced fashion compared to SIRT6 WT. Intracellular stiffness is a property of the cancer cells themselves, which, along with ECM invasiveness, plays a significant role in the progression of HCC. Conclusions: These data suggest that increased intracellular stiffening mirrors increased cell motility and invasive behavior; it can be indicative of suppressed cancer development and progression by the centenarian-associated SIRT6 N308K/A313S mutant. Full article